Mist-generating device

ABSTRACT

A mist-generating device includes: a droplet generating unit that generates, in a third liquid, a functional droplet including a first liquid that is spherical and a second liquid that covers an entirety of the first liquid and has a volatility lower than a volatility of the first liquid; and a mist-generating unit that generates a multilayer mist obtained by atomizing the third liquid containing the functional droplet.

TECHNICAL FIELD

The present invention relates to a mist-generating device.

BACKGROUND ART

As a conventional device that generates a mist used for sanitization,deodorization or the like, the mist-generating device disclosed inPatent Literature (PTL) 1 is known, for example. The mist-generatingdevice according to PTL 1 generates a mist (floatable functionalparticles) by generating electrolyzed water containing a hydroxylradical or hypochlorous acid having a disinfection effect byelectrolysis of water, and atomizing the generated electrolyzed water byelectrostatic atomization by applying a high voltage to the electrolyzedwater with a discharging electrode.

Furthermore, there is a conventional technique of generating a dropletcontaining a plurality of materials (see PTL 2, for example).

The manufacturing device disclosed in PTL 2 has a nozzle including anouter tube and an inner tube that are concentrically formed, and firstpasses a first fluid material through the outer tube and then passes asecond fluid material through the inner tube. After that, themanufacturing device disclosed in PTL 2 stops the flow of the secondfluid material and then stops the flow of the first fluid material. Bysuch a control, the manufacturing device disclosed in PTL 2 forms adroplet containing the first fluid material and the second fluidmaterial covering the first fluid material.

It is possible to contemplate a method for extending the time for whicha mist can dwell in the air, which uses a nozzle having an outer tubeand an inner tube that are concentrically formed, such as the nozzledisclosed in PTL 2, to generate a mist formed by liquid droplets eachcontaining a particle of a liquid and a different liquid covering theparticle (such a mist or a liquid droplet forming the mist will bereferred to as a multilayer mist, hereinafter).

CITATION LIST Patent Literature

PTL 1: Unexamined Patent Application Publication No. 2012-65979

PTL 2: Unexamined Patent Application Publication No. 2001-190943

SUMMARY OF THE INVENTION Technical Problems

For example, with the mist-generating device disclosed in PTL 1, a finemist having a diameter of the order of nanometers to micrometers can begenerated. However, the mist of such a size immediately vaporizes whilefloating in the air. Therefore, the mist dwells in the air for a shorttime and can hardly travel far from the location where the mist isgenerated.

To generate a multilayer mist in the method disclosed in PTL 2, the flowrates of the two liquids ejected from the nozzle need to be extremelyprecisely controlled.

The present invention provides a mist-generating device capable ofgenerating a multilayer mist, using a simple configuration.

Solution to Problems

A mist-generating device according to an aspect of the present inventionincludes: a droplet generating unit configured to generate, in a thirdliquid, a functional droplet including a first liquid that is sphericaland a second liquid that covers an entirety of the first liquid and hasa volatility lower than a volatility of the first liquid; and amist-generating unit configured to generate a multilayer mist obtainedby atomizing the third liquid containing the functional droplet.

Advantageous Effect of Invention

The present invention can provide a mist-generating device capable ofgenerating a multilayer mist, using a simple configuration.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional view showing a configuration of amist-generating device according to Embodiment 1.

FIG. 2 is a cross-sectional view of a functional droplet generated bythe mist-generating device according to Embodiment 1.

FIG. 3 is a schematic diagram showing fission of a multilayer mistgenerated by the mist-generating device according to Embodiment 1.

FIG. 4 is a schematic diagram showing a first example of the dropletgenerating unit of the mist-generating device according to Embodiment 1.

FIG. 5 is a schematic diagram showing a second example of the dropletgenerating unit of the mist-generating device according to Embodiment 1.

FIG. 6 is a schematic diagram showing a third example of the dropletgenerating unit of the mist-generating device according to Embodiment 1.

FIG. 7 is a flowchart showing an operation procedure of themist-generating device according to Embodiment 1.

FIG. 8 is a cross-sectional view showing a configuration of amist-generating device according to Variation 1 of Embodiment 1.

FIG. 9 is a schematic perspective view showing a configuration of amist-generating device according to Variation 2 of Embodiment 1.

FIG. 10 is a partial enlarged cross-sectional view showing aconfiguration of the mist-generating device according to Variation 2 ofEmbodiment 1.

FIG. 11 is a schematic cross-sectional view showing a configuration of amist-generating device according to Embodiment 2.

FIG. 12 is a cross-sectional view showing a configuration of floatablefunctional particle according to Embodiment 2.

FIG. 13 is a schematic perspective view of a nozzle according toEmbodiment 2.

FIG. 14 is a partial enlarged cross-sectional view showing a crosssection of the nozzle taken along the line XIV-XIV in FIG. 13.

FIG. 15 is a schematic cross-sectional view schematically showing howthe mist-generating device according to Embodiment 2 generates afloatable functional particle.

FIG. 16 is a schematic diagram for illustrating an effect of thefloatable functional particle according to Embodiment 2.

FIG. 17 is a schematic cross-sectional view showing a configuration of anozzle of a mist-generating device according to Variation 1 ofEmbodiment 2.

FIG. 18 is a schematic cross-sectional view showing a configuration of anozzle of a mist-generating device according to Variation 2 ofEmbodiment 2.

FIG. 19 is a schematic perspective view showing a configuration of amist-generating device according to Embodiment 3.

FIG. 20 is a diagram schematically showing how a multilayer mist isgenerated by the mist-generating device according to Embodiment 3.

FIG. 21 is a top view showing a configuration of a mist-generatingdevice according to Variation 1 of Embodiment 3.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, embodiments of the present invention will be described indetail with reference to the drawings. Note that each of the followingembodiments shows a specific example of the present invention.Therefore, numerical values, shapes, materials, structural components,the arrangement and connection of the structural components, steps, theprocessing order of the steps, etc. shown in the following embodimentsare mere examples, and thus are not intended to limit the presentinvention. Accordingly, among the structural components described in thefollowing embodiments, structural components not recited in any one ofthe independent claims that indicate the broadest concepts of thepresent invention are described as optional structural components.

Furthermore, the respective figures are schematic diagrams and are notnecessarily accurate illustrations. Therefore, for example, the scale,and so on, in the respective figures do not necessarily match.Furthermore, in the figures, elements which are substantially the sameare given the same reference signs, and overlapping description isomitted or simplified.

In this specification, disinfection means destroying fungi such asStaphylococcus aureus or Staphylococcus epidermidis, bacteria such asEscherichia coli, Pseudomonas sp., or Klebsiella sp., Eumycetesincluding molds such as Cladosporium sp. or Aspergillus, and/or virusessuch as norovirus and reducing the overall number thereof, and is alsoused as a synonym for sanitization or sterilization. The fungi,bacteria, Eumycetes, and viruses described above as targets to be killedare just examples, and the present invention is not limited thereto.

Embodiment 1

[Configuration]

<Overview>

First, with reference to FIGS. 1 to 6, an overview of a configuration ofa mist-generating device according to Embodiment 1 will be described.

FIG. 1 is a schematic cross-sectional view showing a configuration ofmist-generating device 100 according to Embodiment 1. Note that FIG. 1shows cross sections of some components, such as container 10 andejection plate 20 and does not show cross sections of other components,such as droplet generating unit 300.

Mist-generating device 100 according to Embodiment 1 includes container10, droplet generating unit 300, supplying unit 210, mist-generatingunit 400, and control unit 70. Mist-generating unit 400 includesejection plate 20, first electrode 30, and voltage applying unit 40.Ejection plate 20 includes electrode support plate 21 and nozzle 26.

FIG. 1 shows control unit 70 as a functional block. Control unit 70 isimplemented by a microcomputer (microcontroller), for example, and isarranged inside an outer housing (not shown) of mist-generating device100. Control unit 70 may be attached to the exterior of container 10,for example.

Mist-generating device 100 is a spray device that ejects multilayer mistM formed by atomizing third liquid L3 containing functional droplet L.For example, mist-generating device 100 is a device that generatesmultilayer mist M in an electrostatic atomization process, in which ahigh voltage is applied to third liquid L3 to produce an electrostaticforce, which causes atomization of third liquid L3 containing functionaldroplet L. For example, when functional droplet L contains adisinfecting constituent or sanitizing constituent, such as hypochlorousacid or ozone, mist-generating device 100 is used as a disinfectingdevice or a sanitizing device, for example. Note that when functionaldroplet L contains an aromatic constituent, for example, mist-generatingdevice 100 is used as an aroma generator that generates multilayer mistM containing an aromatic constituent.

In mist-generating device 100, supplying unit 210 supplies functionaldroplet L generated by droplet generating unit 300 to container 10, andmist-generating unit 400 atomizes third liquid L3 containing suppliedfunctional droplet L and discharges the resulting mist. Note that thirdliquid L3 is a liquid that is highly volatile and will volatilize anddisappear (or in other words turn into a gas) some time after the liquidis discharged into the air in small quantities.

Mist-generating unit 400 atomizes third liquid L3 containing functionaldroplet L. Mist-generating unit 400 introduces third liquid L3containing functional droplet L to a tip end of nozzle 26 by the actionof a pump (not shown) or the like, and ejects multilayer mist M, whichis formed by atomizing third liquid L3, through opening 29 at the tipend of nozzle 26. In this embodiment, mist-generating unit 400 includesnozzle 26 for discharging third liquid L3 containing functional dropletL, and first electrode 30 that is arranged to be opposed to nozzle 26and applies a voltage to third liquid L3 containing functional droplet Ldischarged from nozzle 26 to atomize third liquid L3 containingfunctional droplet L to generate multilayer mist M.

Specifically, in mist-generating unit 400, voltage applying unit 40applies a high voltage between first electrode 30 and nozzle 26 toproduce an electric field, and multilayer mist M is ejected from opening29 of nozzle 26. Here, the “high voltage” is on the order of 5 kV withrespect to a ground voltage (0 V), but is not particularly limited. Notethat the voltage of first electrode 30 may be positive or negative withrespect to the ground voltage.

A channel that introduces third liquid L3 containing functional dropletL to opening 29 in container 10 is formed in nozzle 26. Third liquid L3containing functional droplet L having flowed in the channel and exitedopening 29 is changed in shape by the electric field to form a Taylorcone. Third liquid L3 containing functional droplet L is atomized at thetip end of the Taylor cone to form multilayer mist M.

Note that, although FIG. 1 shows one nozzle 26, the number of nozzles 26provided on ejection plate 20 is not particularly limited and may betwo, or three or more.

Multilayer mist M generated at the tip end of nozzle 26 is dischargedtoward first electrode 30. In order to discharge multilayer mist M inthe forward direction beyond first electrode 30, through-hole 32 isformed in flat plate part 31 of first electrode 30 at a positiondirectly opposed to nozzle 26. This allows multilayer mist M to bedischarged in the forward direction beyond first electrode 30. Here, the“forward direction” refers to a direction in which multilayer mist M isdischarged and is the opposite direction to nozzle 26 with respect tofirst electrode 30.

Mist-generating unit 400 also charges third liquid L3 containingfunctional droplet L. In this embodiment, mist-generating unit 400performs atomization and charging of third liquid L3 containingfunctional droplet L at the same time by atomizing third liquid L3containing functional droplet L by electrostatic atomization.

FIG. 2 is a cross-sectional view of functional droplet L generated bymist-generating device 100 according to Embodiment 1.

Functional droplet L is a liquid particle that has a predeterminedfunction (effect). For example, functional droplet L is a liquidparticle containing an aromatic constituent that has a function ofgenerating an aroma when coming into contact with air, or a liquidparticle that has a function of killing a target such as a fungus whencoming into contact with the target.

Functional droplet L is formed by first liquid L1 having a granular(that is, spherical) shape, and second liquid L2 having a film-likeshape that has a lower volatility than first liquid L1 and covers thewhole of first liquid L1.

First liquid L1 is a liquid particle that has a predetermined function.For example, first liquid L1 is a liquid particle containing an aromaticconstituent that has a function of generating an aroma when coming intocontact with air, or a liquid particle that has a function of killing atarget such as a fungus when coming into contact with the target. Forexample, when mist-generating device 100 is an aroma generator, firstliquid L1 is an oily liquid containing an aromatic constituent. Whenmist-generating device 100 is a disinfecting device, for example, firstliquid L1 is water containing a disinfection constituent, such ashypochlorous acid.

Second liquid L2 is a liquid that covers the whole of first liquid L1.For example, second liquid L2 is a liquid that has a lower volatilitythan first liquid L1. In other words, second liquid L2 is lesssusceptible to volatilization than first liquid L1, second liquid L2serves to retard vaporization of first liquid L1 in the air. To thisend, the volatility of second liquid L2 is lower than that of firstliquid L1.

Second liquid L2 is formed to have a thickness that allows second liquidL2 to gradually volatilize or be lost until multilayer mist M reaches toa predetermined distance from the location where the mist is generated(that is, mist-generating device 100) so that first liquid L1 is exposedand comes into contact with air. Specifically, second liquid L2 isformed to have a thickness that allows second liquid L2 to volatilize orbe lost to allow first liquid L1 to be exposed and come into contactwith air when a predetermined time has elapsed or, in other words, whenmultilayer mist M generated by mist-generating device 100 has moved apredetermined distance. The predetermined distance can be arbitrarilydetermined. The thickness of second liquid L2 can be any thickness asfar as second liquid L2 completely volatilizes when a predeterminedtime, which is arbitrarily determined in advance, has elapsed or, inother words, when multilayer mist M has moved the predetermineddistance.

For example, the thickness of second liquid L2 can be approximatelyequal to the radius of first liquid L1, greater than the radius of firstliquid L1, or smaller than the radius of first liquid L1.

Alternatively, second liquid L2 may be a liquid that is nonvolatile orhas extremely low volatility and have a structure that has a thicknessthat allows second liquid L2 to be broken when second liquid L2 comesinto contact with an object while second liquid L2 is floating andmoving in the air. In any case, multilayer mist M continues floatingwithout delivering the function until multilayer mist M comes intocontact with an object in the air, and gives the effect of first liquidL1 only after multilayer mist M comes into contact with an object in theair.

In order to prevent mixing of first liquid L1 and second liquid L2, forexample, one of first liquid L1 and second liquid L2 is oily, and theother is aqueous. In addition, in order to prevent functional droplet Lfrom being dissolved in third liquid L3 in container 10, one of secondliquid L2 and third liquid L3 is oily, and the other is aqueous. Thatis, when first liquid L1 and third liquid L3 are aqueous, second liquidis oily, and when first liquid L1 and third liquid L3 are oily, secondliquid L2 is aqueous.

When first liquid L1 is an oily liquid containing an aromaticconstituent, for example, second liquid L2 is an aqueous liquid that hasa lower volatility than first liquid L1. When first liquid L1 is watercontaining a disinfection constituent such as hypochlorous acid, forexample, second liquid L2 is an oily liquid.

With such a configuration, first liquid L1 and second liquid L2 infunctional droplet L are less likely to be mixed with each other.Therefore, with such a configuration, the floating time of multilayermist M in the air can be extended.

Second liquid L2 is a biomaterial or a biocompatible material, forexample. Here, the “biomaterial” refers to a liquid material present inthe human body. The “biocompatible material” refers to a liquid materialthat is artificially produced and has a small influence on the humanbody when the material is taken in the human body. The biomaterial orbiocompatible material is oleic acid, for example.

Note that oleic acid is oily. When second liquid L2 is aqueous, at leastone of first liquid L1 and third liquid L3 may be oleic acid.

If a biomaterial or biocompatible material is used as an oily liquid forfirst liquid L1, second liquid L2, and third liquid L3, the possibilitythat multilayer mist M adversely affects the body of a user when theuser inhales multilayer mist M can be reduced.

For example, third liquid L3 has a higher volatility than second liquidL2. For example, second liquid L2 has a lower volatility than firstliquid L1.

Since third liquid L3 has a high volatility, third liquid L3 volatilizesin a short time while multilayer mist M is existing in the air. Sincethird liquid L3 volatilizes and thus is lost, multilayer mist M becomeslighter. Therefore, multilayer mist M can float for a longer time in theair. As an example, when first liquid L1 is water containing a lowconcentration of, such as 100 ppm or less of, hypochlorous acid, thirdliquid L3 is desirably formed by water containing hypochlorous acid aswith first liquid L1. If first liquid L1 and third liquid L3 are thesame kind of liquid, one supplying unit can be shared for replenishing(supplying) first liquid L1 and third liquid L3 to droplet generatingunit 300, so that the structure of the device can be simplified.However, when first liquid L1 is an expensive liquid (such as an aromaoil), it is desirable that the device has separate supplying units forsupplying first liquid L1 and third liquid L3 to nozzle 26, and aninexpensive liquid, which is different from first liquid L1, is used asthird liquid L3 to reduce the cost of the liquid materials.

The outer diameter (particle diameter) of functional droplet L is equalto or smaller than 10 μm, for example.

With such a configuration, multilayer mist M does not fall under its ownweight in a short time, and can float in the air for an elongated time.

The particle diameter of functional droplet L may be equal to or smallerthan 5 μm. The particle diameter of functional droplet L may also beequal to or greater than 10 nm and equal to or smaller than 3 μm.

The volume of second liquid L2 in functional droplet L contained inmultilayer mist M is preferably small enough not to adversely affect theuser who inhales or otherwise takes in multilayer mist M.

As disclosed on the webpage of International Pharmaceutical ExcipientsCouncil Japan (URL: http://www.jpec.gr.jp/document/safety.html), themaximum dose per day of oleic acid as an inhalant is 0.1668 mg.Therefore, by setting the thickness of second liquid L2 so that theamount of inhalation is equal to or smaller than 0.1688 mg, the safetyof the living human body can be assured even if multilayer mist Mcontaining oleic acid as second liquid L2 is sprayed into the space inwhich the human body is present. For example, when second liquid L2 isoleic acid, which is oily, the particle diameter of functional droplet Lis 5 μm, and mist-generating device 100 sprays multilayer mist M into aspace having a volume of 20 m³ at a rate of 0.1 mL/h for up to six hoursper day, the thickness of second liquid L2 in functional droplet L is onthe order of 10 nm. In this way, multilayer mist M can be prevented fromadversely affecting the human body. The thickness of second liquid L2 infunctional droplet L is controlled by adjusting the size or shape ofdroplet generating units 300, 300 a, and 300 b described later and theflowrate or the like of first liquid L1, second liquid L2, and thirdliquid L3 flowing in the channels of droplet generating units 300, 300a, and 300 b described later.

FIG. 3 is a schematic diagram showing fission of multilayer mist Mgenerated by mist-generating device 100 according to Embodiment 1.

Multilayer mist M is an aggregate of liquid particles of third liquid L3containing one or more functional droplet L. Multilayer mist M is anaggregate of fine liquid particles having a diameter of 100 μm or less.

As shown in part (a) of FIG. 3, multilayer mist M is electrostaticallyatomized and discharged from nozzle 26 shown in FIG. 1 in the form of adroplet containing functional droplet L and electric charge E.

Note that, although part (a) of FIG. 3 shows a case where threefunctional droplets L are contained as an example, multilayer mist M cancontain any number of functional droplets L. Although parts (a) and (b)of FIG. 3 show a case where electric charge E is negative as an example,electric charge E may be positive. The polarity of electric charge Edepends on whether the voltage applied to first electrode 30 is positiveor negative.

As shown in part (b) of FIG. 3, electric charge E then causes a Rayleighfission of multilayer mist M shown in part (a) of FIG. 3, and multilayermist M splits into a plurality of multilayer mists M1.

As shown in part (c) of FIG. 3, third liquid L3 in multilayer mist M1shown in part (b) of FIG. 3 then volatilizes, and a plurality ofmultilayer mists M2 having functional droplet L exposed to the air isthus generated.

Multilayer mist M discharged from nozzle 26 has a particle diameter ofthe order of several tens of p.m immediately after multilayer mist M isdischarged. However, multilayer mist M immediately splits, and thirdliquid L3 volatilizes. In this way, multilayer mist M2 is formed whichis formed by functional droplet L alone and has a particle diameter of10 μm or less. To this end, third liquid L3 has a volatility. Thirdliquid L3 preferably volatilizes in a short time in the air. Forexample, third liquid L3 has a higher volatility than second liquid L2.For example, third liquid L3 also has a higher volatility than firstliquid L1.

In the following description, multilayer mist M will be basicallydescribed as multilayer mist M containing first liquid L1 having theshape of a spherical core and second liquid L2 covering the entiresurface of first liquid L1. However, the present invention is notlimited thereto. For example, multilayer mist M may be discharged intothe air by atomizing third liquid L3 containing multilayer functionaldroplet L formed by second liquid L2 the entire surface of which iscovered by a fourth liquid (not shown) the entire surface of which iscovered by a fifth liquid (not shown), which is different from thefourth liquid. In that case, if first liquid L1 is oily, second liquidL2, which forms a layer adjacent first liquid L1, is desirably aqueousin order to prevent mixing thereof. Similarly, the fourth liquid (notshown), which forms a layer adjacent to second liquid L2, is desirablyoily in order to prevent mixing thereof, and third liquid L3 isdesirably aqueous. On the other hand, if first liquid L1 is aqueous,second liquid L2, which forms a layer adjacent first liquid L1, isdesirably oily in order to prevent mixing thereof. Similarly, the fourthliquid (not shown), which forms a layer adjacent to second liquid L2, isdesirably aqueous in order to prevent mixing thereof, and third liquidL3 is desirably oily. As described above, as far as a predeterminedweight is not exceeded, this concept can be extended to n layers (nrepresents a natural number). This concept is independent from whetherthe mist has electric charge E or not.

In the following, each component of mist-generating device 100 will bedescribed in detail.

<Container>

Container 10 is a container that accommodates third liquid L3. Whensecond liquid L2 is an oily liquid, for example, third liquid L3 is anaqueous liquid. When second liquid L2 is water containing a disinfectionconstituent such as hypochlorous acid, for example, third liquid L3 isan oily liquid.

Container 10 is made of a metal material such as stainless steel, forexample. However, container 10 may be made of a resin material.Container 10 may be made of a material having one or both of acidresistance and alkali resistance.

Container 10 has the shape of a cylinder with an open top, for example.However, the shape of container 10 is not limited thereto. Container 10may have the shape of a cube, a rectangular parallelepiped, or a flattray. The open top of container 10 is covered by ejection plate 20.

<Ejection Plate>

Ejection plate 20 has opening 29 through which third liquid L3containing functional droplet L is ejected. Specifically, ejection plate20 includes electrode support plate 21 having a planar shape, and nozzle26. Opening 29 is formed at a tip end of nozzle 26.

Electrode support plate 21 is a plate-like member that supports nozzle26. Electrode support plate 21 is made of a resin material, for example.However, electrode support plate 21 may be made of a metal material.Electrode support plate 21 may be made of a material having one or bothof acid resistance and alkali resistance.

Nozzle 26 is fixed to electrode support plate 21 by press-fitting. Forexample, a through-hole is formed in electrode support plate 21 at alocation where opening 29 is to be provided, and nozzle 26 is insertedinto the through-hole and fixed. Electrode support plate 21 is a flatplate having a uniform thickness. However, the present invention is notthereto, and electrode support plate 21 may be a curved plate.

Electrode support plate 21 is fixed to container 10. Electrode supportplate 21 may be made of the same material as container 10 and formedintegrally with container 10.

Nozzle 26 is a nozzle for discharging third liquid L3 containingfunctional droplet L to the outside of container 10. Specifically,nozzle 26 is supported by electrode support plate 21, and dischargesthird liquid L3 containing functional droplet L in container 10 to theoutside of container 10. Nozzle 26 projects toward first electrode 30from electrode support plate 21. Nozzle 26 has opening 29 at a tip endthereof. Nozzle 26 also has an opening at a rear end thereof (that is,an end on the side of container 10), and a channel extending from theopening to opening 29.

Nozzle 26 has the shape of a cylinder having uniform inner and outerdiameters, for example. The inner diameter is the diameter of thechannel, and is 0.3 mm, for example. However, the present invention isnot limited thereto. The outer diameter is 0.5 mm, for example. However,the present invention is not limited thereto. For example, the outerdiameter may fall within a range from 0.5 mm to 1.5 mm inclusive. Thechannel formed in nozzle 26 has the shape of a cylinder having a uniformcross-sectional area, for example.

Note that at least one of the inner and outer diameters of nozzle 26 maybe tapered from the rear end toward the tip end. For example, theopening at the rear end may be smaller than opening 29 at the tip end,and the channel connecting these openings may have the shape of atruncated cone.

The rear end of nozzle 26 is positioned at a location where the rear endis in contact with third liquid L3 in container 10. Specifically, therear end of nozzle 26 is located inside container 10. This allows thirdliquid L3 to be introduced from the opening at the rear end of nozzle 26to opening 29 at the tip end thereof through the channel in nozzle 26.

Nozzle 26 stands perpendicularly to a principal surface (specifically, asurface closer to first electrode 30) of electrode support plate 21. Theprincipal surface is a surface of electrode support plate 21 that isopposed to first electrode 30 and is on the opposite side to container10. The ratio of height to outer diameter (referred to as an aspectratio, hereinafter) of nozzle 26 is preferably equal to or greater than4. The height of nozzle 26 is represented by the distance from the tipend of nozzle 26 to the principal surface. The height is equal to orgreater than 2 mm, for example. The greater the aspect ratio of nozzle26, the more easily the electric field is concentrated at the tip end ofnozzle 26. Therefore, the aspect ratio of nozzle 26 can be equal to orgreater than 6, for example.

The material of nozzle 26 is not particularly limited. For example,nozzle 26 may be a metal material having a conductivity, such asstainless steel. Nozzle 26 may be made of a material having one or bothof acid resistance and alkali resistance. Nozzle 26 may be made of amaterial having insulation properties, such as resin.

For example, if nozzle 26 is made of a conductive material, nozzle 26can serve as an electrode (second electrode) paired with first electrode30. In this embodiment, nozzle 26 is paired with first electrode 30, anda voltage is applied to third liquid L3 discharged from nozzle 26 toproduce multilayer mist M.

Note that mist-generating device 100 may be provided with an electrodehoused in container 10, as a second electrode paired with firstelectrode 30, for example. In that case, voltage applying unit 40 iselectrically connected to first electrode 30 and the second electrode.In that case, nozzle 26 may be made of a material having insulationproperties, such as resin.

Although FIG. 1 shows one nozzle 26, the number of nozzles 26 providedon ejection plate 20 is not particularly limited, and two, or three ormore nozzles 26 may be provided. In that case, through-hole 32 ispreferably formed in first electrode 30 at a location directly opposedto each of the plurality of nozzles 26.

<First Electrode>

First electrode is an opposed electrode that is arranged outsidecontainer 10 in such a manner that through-hole 32 is opposed to opening29. Specifically, first electrode 30 is arranged outside container 10 tobe opposed to nozzle 26 paired with first electrode 30. When a voltageis applied between first electrode 30 and nozzle 26, third liquid L3containing functional droplet L discharged from the tip end of nozzle 26is atomized. First electrode 30 is arranged in parallel with electrodesupport plate 21 of ejection plate 20, for example. Specifically, a rearsurface of first electrode 30 is in parallel with the principal surfaceof electrode support plate 21.

First electrode 30 is made of a metal material having a conductivity,such as stainless steel. First electrode 30 may be made of a materialhaving one or both of acid resistance and alkali resistance.

First electrode 30 includes flat plate part 31 and through-hole 32. Flatplate part 31 is conductive and is electrically connected to voltageapplying unit 40. Flat plate part 31 has a substantially uniformthickness. Nozzle 26 is also conductive and is electrically connected tovoltage applying unit 40.

Through-hole 32 passes through flat plate part 31 in the thicknessdirection (that is, the back-and-forth direction). Through-hole 32 isprovided to allow atomized third liquid L3 containing functional dropletL ejected from opening 29, that is, multilayer mist M, to pass throughflat plate part 31. Through-hole 32 has a flat cylindrical shape. Theshape of the opening of through-hole 32 is not limited to a circle butcan be a square, a rectangle, or an ellipse, for example.

The diameter of the opening of through-hole 32 is not particularlylimited. For example, the diameter falls within a range from 1 mm to2.25 mm inclusive. The diameter of the opening of through-hole 32 may befive or more times greater than and ten or less times smaller than theouter diameter of nozzle 26. Multilayer mist M discharged from the tipend of the Taylor cone spreads in a conical shape. Therefore, thegreater the diameter of the opening of through-hole 32, the moremultilayer mist M passes through through-hole 32.

<Voltage Applying Unit>

Voltage applying unit 40 applies a predetermined voltage between thirdliquid L3 and first electrode 30. Specifically, voltage applying unit 40is connected to first electrode 30 and nozzle 26, and applies a voltageso as to produce a predetermined potential difference between firstelectrode 30 and nozzle 26. For example, nozzle 26 is grounded, andthird liquid L3 is at the ground potential. Voltage applying unit 40applies a potential to first electrode 30, thereby applying apredetermined voltage between first electrode 30 and third liquid L3.Note that voltage applying unit 40 may apply a positive voltage to firstelectrode 30 or apply a negative voltage to first electrode 30.

The predetermined voltage applied by voltage applying unit 40 is adirect-current voltage equal to or higher than 3.5 kV and equal to orlower than 10 kV. Alternatively, the predetermined voltage may be equalto or higher than 4.5 kV and equal to or lower than 8.5 kV. Note thatthe predetermined voltage may be a pulse voltage, a pulsating voltage,or an alternating-current voltage.

Specifically, voltage applying unit 40 is implemented by a power supplycircuit including a converter or the like. For example, voltage applyingunit 40 applies a voltage to third liquid L3 by generating apredetermined voltage based on an electric power received from anexternal power supply, such as a utility power supply, and applying thegenerated voltage between first electrode 30 and nozzle 26.

<Supplying Unit>

Supplying unit 210 supplies functional droplet L generated by dropletgenerating unit 300 into third liquid L3 in container 10. Supplying unit210 supplies third liquid L3 containing functional droplet L generatedby droplet generating unit 300 to mist-generating unit 400. Supplyingunit 210 is a pump, for example. Supplying unit 210 supplies functionaldroplet L from droplet generating unit 300 into third liquid L3 incontainer 10 through piping connecting droplet generating unit 300 tothe interior of container 10. Note that supplying unit 210 has only tosupply functional droplet L to container 10 and may be provided with asolenoid valve or the like.

<Control Unit>

Control unit 70 is a controlling device that controls the overalloperation of mist-generating device 100. Specifically, control unit 70controls operations of voltage applying unit 40 and supplying unit 210.For example, control unit 70 controls voltage applying unit 40, therebycontrolling the timing of application of a voltage between firstelectrode 30 and nozzle 26 and the magnitude of the voltage, forexample.

Control unit 70 is implemented by a microcontroller, for example.Specifically, control unit 70 is implemented by a nonvolatile memorystoring a program, a volatile memory used as a temporary storage areafor execution of the program, an input/output port, a processor thatexecutes the program, and the like. Control unit 70 may be implementedby a dedicated electronic circuit that realizes each operation.

Note that control unit 70 has only to be able to control voltageapplying unit 40 and supplying unit 210, and may control voltageapplying unit 40 and supplying unit 210 by transmitting a radio signalor may be connected to voltage applying unit 40 and supplying unit 210by a control line or the like.

<Droplet Generating Unit>

Next, with reference to FIGS. 4 to 6, a specific configuration of thedroplet generating unit of mist-generating device 100 according toEmbodiment 1 will be described.

Note that FIGS. 4 to 6 are enlarged views of a part of the dropletgenerating unit that generates functional droplet L, in whichillustration of the supplying unit that supplies first liquid L1, secondliquid L2, and third liquid L3 to the part that generates functionaldroplet L is omitted. In FIGS. 4 and 5, each component is indicated byhatched lines, although the hatched lines do not represent the crosssection of the component.

FIG. 4 is a schematic diagram showing a first example of the dropletgenerating unit of mist-generating device 100 according to Embodiment 1.

The droplet generating unit of mist-generating device 100 is a devicethat generates functional droplet L in third liquid L3, functionaldroplet L containing first liquid L1 that has a spherical shape andsecond liquid L2 that has a lower volatility than first liquid L1 andcovers the whole of first liquid L1.

Droplet generating unit 300 in the first example includes microchannelchip 301, which is a microfluidic device that has a channel having asize of the order of micrometers, and a supplying unit (not shown) thatsupplies first liquid L1, second liquid L2, and third liquid L3 tomicrochannel chip 301. FIG. 4 is a partial enlarged view of microchannelchip 301.

Microchannel chip 301 is a plate-like body in which a channel is formedthrough which first liquid L1, second liquid L2, and third liquid L3pass. The channel of microchannel chip 301 branches in a T-shaped,X-shaped, and/or Y-shaped configuration. In this embodiment,microchannel chip 301 has first liquid channel 311 through which firstliquid L1 passes, second liquid channel 321 through which second liquidL2 passes, mixing channel 322 that is connected to first liquid channel311 and second liquid channel 321 and allows the whole of first liquidL1 to be covered by second liquid L2, and third liquid channel 331 thatis connected to mixing channel 322 and allows the whole of first liquidL1 and second liquid L2 to be covered by third liquid L3.

Microchannel chip 301 is made of a glass material, a resin material, oran inorganic material such as metal or silicon, for example.

For example, first liquid L1 is introduced to first liquid channel 311.Specifically, first liquid L1 is introduced into microchannel chip 301in the direction indicated by arrow A1.

Second liquid L2 is introduced to second liquid channel 321.Specifically, second liquid L2 is introduced into microchannel chip 301in the direction indicated by arrow A2. The direction of arrow A1, whichis the direction in which first liquid L1 moves, is perpendicular to thedirection of arrow A2, which is the direction in which second liquid L2moves. Therefore, by appropriately adjusting the amounts of first liquidL1 and second liquid L2 flowing into microchannel chip 301, first liquidL1 is divided into spherical liquid particles. In this way, at theintersection (point of connection) between first liquid channel 311 andsecond liquid channel 321, second liquid L2 covers first liquid L1 so asto form first liquid L1 into spherical particles, and flows throughmixing channel 322.

Third liquid L3 is introduced to third liquid channel 331. Specifically,third liquid L3 is introduced into microchannel chip 301 in thedirection indicated by arrow A3. The direction of arrow A2, which is thedirection in which second liquid L2 and spherical particles of firstliquid L1 move, is perpendicular to the direction of arrow A3, which isthe direction in which third liquid L3 moves. Therefore, byappropriately adjusting the amounts of second liquid L2 and third liquidL3 flowing into microchannel chip 301, second liquid L2 is divided intospherical liquid particles containing spherical particles of firstliquid L1. The spherical particles of second liquid L2 containingspherical particles of first liquid L1 thus formed are functionaldroplets L. In other words, at the intersection (point of connection)between mixing channel 322 and third liquid channel 331, third liquid L3covers second liquid L2 so as to form second liquid L2 covering firstliquid L1 into spherical particles. In this way, functional droplet Lcovered by third liquid L3 is generated in microchannel chip 301.

Functional droplet L moves in the direction indicated by arrow A4, andis supplied into third liquid L3 in container 10 by supplying unit 210,for example.

As described above, the first example of droplet generating unit 300 ismicrochannel chip 301 that has first liquid channel 311 through whichfirst liquid L1 passes, second liquid channel 321 through which secondliquid L2 passes, mixing channel 322 that is connected to first liquidchannel 311 and second liquid channel 321 and allows the whole of firstliquid L1 to be covered by second liquid L2, and third liquid channel331 that is connected to mixing channel 322 and allows the whole offirst liquid L1 and second liquid L2 to be covered by third liquid L3.

With such a configuration, functional droplet L contained in thirdliquid L3 can be generated with a simple configuration.

FIG. 5 is a schematic diagram showing a second example of the dropletgenerating unit of mist-generating device 100 according to Embodiment 1.

Droplet generating unit 300 a includes microchannel chip 301 a, and asupplying unit (not shown) that supplies first liquid L1, second liquidL2, and third liquid L3 to microchannel chip 301 a. FIG. 5 is a partialenlarged view of microchannel chip 301 a.

Microchannel chip 301 a is a plate-like body in which channels areformed through which first liquid L1, second liquid L2, and third liquidL3 pass. Microchannel chip 301 a is made of a glass material or a resinmaterial, for example.

First liquid L1 is introduced to first liquid channel 311 a inmicrochannel chip 301 a in the direction indicated by arrow A5.

Second liquid L2 is introduced to second liquid channel 321 a inmicrochannel chip 301 a in the direction indicated by arrow A6. Secondliquid L2 is also introduced to second liquid channel 321 b inmicrochannel chip 301 a in the direction indicated by arrow A7. ArrowsA6 and A7 are straight, are in parallel with each other, and indicatethe opposite directions, for example.

In this way, second liquid L2 is positioned in mixing channel 322 a inmicrochannel chip 301 a to cover first liquid L1.

Third liquid L3 is introduced to third liquid channel 331 a inmicrochannel chip 301 a in the direction indicated by arrow A8.

Third liquid L3 is also introduced to third liquid channel 331 b inmicrochannel chip 301 a in the direction indicated by arrow A9. ArrowsA8 and A9 are straight, are in parallel with each other, and indicatethe opposite directions, for example.

In this way, third liquid L3 divides first liquid L1 and second liquidL2 covering first liquid L1 into spherical functional droplets L.

Functional droplet L moves in the direction indicated by arrow A10, andis supplied into third liquid L3 in container 10 by supplying unit 210,for example.

FIG. 6 is a schematic diagram showing a third example of the dropletgenerating unit of mist-generating device 100 according to Embodiment 1.

Droplet generating unit 300 b includes complex nozzle 301 b, and asupplying unit (not shown) that supplies first liquid L1, second liquidL2, and third liquid L3 to complex nozzle 301 b. FIG. 6 is a partialenlarged cross-sectional view of complex nozzle 301 b.

Complex nozzle 301 b is a cylindrical nozzle in which channels areformed through which first liquid L1, second liquid L2, and third liquidL3 pass. Complex nozzle 301 b is made of a metal material, a glassmaterial, or a resin material, for example.

Complex nozzle 301 b includes a nozzle to which first liquid L1 isintroduced, a nozzle for ejecting functional droplet L generated incomplex nozzle 301 b, and a nozzle that covers and connects thesenozzles.

First liquid L1 is introduced from first liquid channel 311 b intocomplex nozzle 301 b in the direction indicated by arrow A11.

Second liquid L2 is contained in advance in complex nozzle 301 b.

When an appropriate amount of first liquid L1 is introduced from firstliquid channel 311 b into complex nozzle 301 b in the directionindicated by arrow A11, first liquid L1 is divided into spherical liquidparticles, which are covered by second liquid L2.

Third liquid L3 is introduced from third liquid channels 331 c and 331 din complex nozzle 301 b in the directions indicated by arrows A12 andA13, which are in parallel with and indicate the opposite directions toarrow A14, which indicates the direction in which functional droplet Lis ejected.

With such a configuration, third liquid L3 divides second liquid L2covering first liquid L1 into spherical functional droplets L, movesalong with functional droplets L in the direction indicated by arrowA14, and is supplied into third liquid L3 in container 10 by supplyingunit 210, for example.

Note that first liquid channel 311, second liquid channel 321, mixingchannel 322, and third liquid channel 331 in microchannel chip 301 mayhave different wettabilities depending on whether first liquid L1,second liquid L2, and third liquid L3 are aqueous or oily.

For example, when first liquid L1 is aqueous, first liquid channel 311through which first liquid L1 passes has a higher wettability to water(water phase) than to oil (oil phase).

For example, when second liquid L2 is oily, second liquid channel 321through which second liquid L2 passes and mixing channel 322 have ahigher wettability to oil than to water.

For example, when third liquid L3 is aqueous, third liquid channel 331through which third liquid L3 passes has a higher wettability to waterthan to oil.

With such a configuration, first liquid L1, second liquid L2, and thirdliquid L3 can more easily flow in the channels through which firstliquid L1, second liquid L2, and third liquid L3 pass. With such aconfiguration, in addition, for example, second liquid L2 can moreeasily cover first liquid L1 so as to form first liquid L1 intospherical particles at the intersection between first liquid channel 311and second liquid channel 321. With such a configuration, in addition,third liquid L3 can more easily cover second liquid L2 so as to formsecond liquid L2 covering first liquid L1 into spherical particles atthe intersection (point of connection) between mixing channel 322 andthird liquid channel 331.

Note that the wettability of the channels is adjusted by changing thematerial of microchannel chip 301 or modifying the shapes of the innersurfaces of the channels, for example. Although microchannel chip 301shown in FIG. 4 is constituted by one microchannel chip, microchannelchip 301 may be a combination of a plurality of microchannel chipshaving channels having different wettabilities.

The above description of the wettability of the channels applies to thewettability of the channels of droplet generating units 300 a and 300 b.

[Operation]

Next, with reference to FIG. 7, an operation of mist-generating device100 according to Embodiment 1 will be described.

First, droplet generating unit 300 performs a first step of generatingfunctional droplet L (step S101).

Supplying unit 210 then performs a second step of supplying functionaldroplet L generated by droplet generating unit 300 into third liquid L3in container 10 (step S102).

Mist-generating unit 400 then performs a third step of atomizing thirdliquid L3 containing functional droplet L (step S103).

Mist-generating unit 400 also performs a fourth step of chargingatomized third liquid L3 containing functional droplet L (step S104).Note that, in this embodiment, mist-generating unit 400 atomizes thirdliquid L3 containing functional droplet L in an electrostaticatomization process, so that mist-generating unit 400 charges thirdliquid L3 while atomizing third liquid L3. That is, in this embodiment,steps S103 and S104 are performed at the same time in the electrostaticatomization process performed by mist-generating unit 400.

[Effects and the Like]

As described above, the mist-generating method according to Embodiment 1includes a first step of generating functional droplet L that containsfirst liquid L1 that has a spherical shape and second liquid L2 that hasa lower volatility than first liquid L1 and covers the whole of firstliquid L1, a second step of supplying functional droplet L into thirdliquid L3, and a third step of atomizing third liquid L3 containingfunctional droplet L.

According to such a method, as with the method according to the relatedart for covering an atomized liquid with a different liquid whenatomizing a liquid, functional droplet L containing first liquid L1covered by second liquid L2 can be atomized. According to themist-generating method according to Embodiment 1, the flowrate of theliquid discharged from the nozzle does not have to be preciselycontrolled unlike the related art, and therefore, multilayer mist M canbe generated more simply than conventional.

For example, the mist-generating method according to Embodiment 1further includes a fourth step of charging third liquid L3 containingfunctional droplet L.

According to such a method, multilayer mist M splits into a plurality ofmultilayer mists M1 by Rayleigh fission. Third liquid L3 of theplurality of multilayer mists M1 resulting from the fission ofmultilayer mist M has a greater area of contact with air than thirdliquid L3 of multilayer mist M yet to split. Therefore, third liquid L3of the plurality of multilayer mists M1 resulting from the fission ofmultilayer mist M more easily vaporizes than third liquid L3 ofmultilayer mist M yet to split. Therefore, multilayer mists M2, whichare formed by functional droplets L and do not contain third liquid L3,can be more quickly discharged into the air.

For example, in the mist-generating method according to Embodiment 1,the third step and the fourth step described above are performed at thesame time by atomizing third liquid L3 containing functional droplet Lin the electrostatic atomization process.

According to such a method, atomization and charging of third liquid L3containing functional droplet L can be performed at the same time bymist-generating unit 400. Therefore, according to such a method, thirdliquid L3 containing functional droplet L can be simply charged.

For example, third liquid L3 has a higher volatility than second liquidL2.

Therefore, third liquid L3 contained in multilayer mist M immediatelyvolatilizes. Therefore, according to such a method, multilayer mist M2,which is formed by functional droplet L and does not contain thirdliquid L3, can be immediately discharged into the air.

Mist-generating device 100 according to Embodiment 1 includes dropletgenerating unit 300 that generates functional droplet L in third liquidL3, functional droplet L containing first liquid L1 that has a sphericalshape and second liquid L2 that has a lower volatility than first liquidL1 and covers the whole of first liquid L1, and mist-generating unit 400that atomizes third liquid L3 containing functional droplet L. In thisembodiment, mist-generating device 100 further includes supplying unit210 that supplies third liquid L3 containing functional droplet Lgenerated by droplet generating unit 300 to mist-generating unit 400.

With such a configuration, without the need of the precise control forcovering an atomized liquid with a different liquid when atomizing aliquid through a nozzle according to the related art, functional dropletL containing first liquid L1 covered by second liquid L2 can beatomized. With mist-generating device 100, multilayer mist M can be moresimply generated than conventional.

Since mist-generating device 100 includes supplying unit 210, dropletgenerating unit 300 and mist-generating unit 400 can be arranged at adistance. Therefore, the convenience of mist-generating device 100 canbe improved.

(Variation 1)

FIG. 8 is a cross-sectional view showing a configuration ofmist-generating device 100 a according to Variation 1 of Embodiment 1.

Note that the components of mist-generating device 100 a according toVariation 1 of Embodiment 1 that are substantially the same as those ofmist-generating device 100 according to Embodiment 1 are denoted by thesame reference numerals, and descriptions thereof will be simplified oromitted.

Mist-generating device 100 a according to Variation 1 of Embodiment 1differs from mist-generating device 100 according to Embodiment 1 inthat third liquid L3 is atomized by ultrasonic vibration.

Mist-generating device 100 a includes container 10, supplying unit 210,droplet generating unit 300, mist-generating unit 401, chargingelectrode 30 a, voltage applying unit 40 a, and control unit 71.

Mist-generating unit 401 is an ultrasonic generating device that appliesan ultrasonic vibration to third liquid L3 containing functional dropletL in container 10. Mist-generating unit 401 is arranged at a locationwhere mist-generating unit 401 is in contact with third liquid L3 incontainer 10, for example. Mist-generating unit 401 is an ultrasonictransducer, for example. Note that mist-generating unit 401 has only tobe able to apply an ultrasonic vibration to third liquid L3 in container10, and may be arranged outside container 10 and apply an ultrasonicvibration to third liquid L3 in container 10 by applying the ultrasonicvibration to container 10.

Charging electrode 30 a is an electrode for charging multilayer mist M.Charging electrode 30 a is a ring electrode having an annular shape, forexample, and generates multilayer mist M having electric charge E bycharging multilayer mist M passing through the inner space of the ringelectrode.

As described above, mist-generating device 100 a includesmist-generating unit 401 that generates multilayer mist M, and acharging unit that has charging electrode 30 a that charges multilayermist M. Mist-generating device 100 a generates multilayer mist M havingelectric charge E by atomizing third liquid L3 containing functionaldroplet L to generate multilayer mist M having no electric charge E andthen charging multilayer mist M with charging electrode 30 a.

Voltage applying unit 40 a is connected to charging electrode 30 a, andapplies a predetermined voltage to charging electrode 30 a. Voltageapplying unit 40 a charges multilayer mist M passing through theperiphery of charging electrode 30 a by applying a potential to chargingelectrode 30 a. Note that, although voltage applying unit 40 a applies anegative voltage to charging electrode 30 a in FIG. 8, voltage applyingunit 40 a may apply a positive voltage to charging electrode 30 a.

Note that the predetermined voltage applied by voltage applying unit 40a may be a pulse voltage, a pulsating voltage, or an alternating-currentvoltage.

Voltage applying unit 40 a is implemented by a power supply circuitincluding a converter or the like, for example. For example, voltageapplying unit 40 a generates a predetermined voltage based on anelectric power received from an external power supply, such as a utilitypower supply, and applies the generated voltage to charging electrode 30a.

Control unit 71 is a controlling device that controls the overalloperation of mist-generating device 100 a. Specifically, control unit 71controls operations of voltage applying unit 40 a, supplying unit 210,and mist-generating unit 401. For example, control unit 71 controlsmist-generating unit 401, thereby controlling the timing of generationof multilayer mist M by application of an ultrasonic vibration to thirdliquid L3 in container 10.

Control unit 71 is implemented by a microcontroller, for example.Specifically, control unit 71 is implemented by a nonvolatile memorystoring a program, a volatile memory used as a temporary storage areafor execution of the program, an input/output port, a processor thatexecutes the program, and the like. Control unit 71 may be implementedby a dedicated electronic circuit that realizes each operation.

Note that control unit 71 has only to be able to control voltageapplying unit 40 a, supplying unit 210, and mist-generating unit 401,and may control voltage applying unit 40 a, supplying unit 210, andmist-generating unit 401 by transmitting a radio signal or may beconnected to voltage applying unit 40 a, supplying unit 210, andmist-generating unit 401 by a control line or the like.

According to the mist-generating method according to Variation 1 ofEmbodiment 1, unlike the mist-generating method according to Embodiment1, atomized third liquid L3 containing functional droplet L is charged.That is, according to the mist-generating method according to Variation1 of Embodiment 1, multilayer mist M having electric charge E isgenerated by charging a multilayer mist generated by mist-generatingunit 401. In other words, in the mist-generating method according toVariation 1 of Embodiment 1, step S103 shown in FIG. 7 is performedafter step S104 shown in FIG. 7.

Furthermore, mist-generating unit 401 of mist-generating device 100 aaccording to Variation 1 of Embodiment 1 is an ultrasonic vibrationgenerating device that generates multilayer mist M by atomizing thirdliquid L3 by applying an ultrasonic vibration to third liquid L3containing functional droplet L. In addition, mist-generating device 100a includes charging electrode 30 a for charging multilayer mist M.

With such a configuration, atomization and charging of third liquid L3containing functional droplet L can be separately performed, so that theamount of multilayer mist M generated and the amount of charge ofmultilayer mist M can be separately controlled. Therefore, with such aconfiguration, the amount of multilayer mist M generated can becontrolled to a desired amount.

(Variation 2)

FIG. 9 is a perspective view showing a configuration of mist-generatingdevice 100 b according to Variation 2 of Embodiment 1. FIG. 10 is apartial enlarged cross-sectional view showing a configuration ofmist-generating device 100 b according to Variation 2 of Embodiment 1.

Note that the components of mist-generating device 100 b according toVariation 2 of Embodiment 1 that are substantially the same as those ofmist-generating device 100 according to Embodiment 1 are denoted by thesame reference numerals, and descriptions thereof will be simplified oromitted. In FIG. 9, illustration of some components, such as voltageapplying unit 40, is omitted.

Mist-generating device 100 b includes droplet generating unit 300,mist-generating unit 400, and control unit 72. Droplet generating unit300 includes microchannel chip 301, and supplying units 211, 212, and213.

FIG. 9 is a schematic perspective view showing the whole of microchannelchip 301, which is mist-generating unit 400 shown in FIG. 4.

Microchannel chip 301 has first liquid inlet 310 to which first liquidL1 is introduced by supplying unit 211, second liquid inlet 320 to whichsecond liquid L2 is introduced by supplying unit 212, and third liquidinlet 330 to which third liquid L3 is introduced by supplying unit 213.First liquid inlet 310 is connected to first liquid channel 311 shown inFIG. 4. Second liquid inlet 320 is connected to second liquid channel321 shown in FIG. 4. Third liquid inlet 330 is connected to third liquidchannel 331 shown in FIG. 4.

Supplying unit 211 supplies first liquid L1 to first liquid inlet 310 ofmicrochannel chip 301. Supplying unit 211 is a pump, for example, andsupplies first liquid L1 from a tank (not shown) containing first liquidL1 to first liquid inlet 310 through piping. Note that supplying unit211 has only to be able to supply first liquid L1 to first liquid inlet310 and may be provided with a solenoid valve or the like.

Supplying unit 212 supplies second liquid L2 to second liquid inlet 320of microchannel chip 301. Supplying unit 212 is a pump, for example, andsupplies second liquid L2 from a tank (not shown) containing secondliquid L2 to second liquid inlet 320 through piping. Note that supplyingunit 212 has only to be able to supply second liquid L2 to second liquidinlet 320 and may be provided with a solenoid valve or the like.

Supplying unit 213 supplies third liquid L3 to third liquid inlet 330 ofmicrochannel chip 301. Supplying unit 213 is a pump, for example, andsupplies third liquid L3 from a tank (not shown) containing third liquidL3 to third liquid inlet 330 through piping. Note that supplying unit213 has only to be able to supply third liquid L3 to third liquid inlet330 and may be provided with a solenoid valve or the like.

Microchannel chip 301 has reservoir 340.

Reservoir 340 is an accommodation unit that is connected to third liquidchannel 331 and stores third liquid L3 containing functional droplet L.

As shown in FIG. 10, reservoir 340 is connected to container 10 a.

Container 10 a is a container that accommodates third liquid L3containing functional droplet L. Container 10 a is connected toreservoir 340 of microchannel chip 301 so that third liquid L3containing functional droplet L can move therebetween. In thisembodiment, container 10 a is open at the bottom and connected toreservoir 340.

Control unit 72 shown in FIG. 9 is a controlling device that controlsthe overall operation of mist-generating device 100 b. Specifically,control unit 72 controls operations of voltage applying unit 40 andsupplying units 211, 212, and 213, for example. For example, controlunit 72 controls voltage applying unit 40, thereby controlling thetiming of application of a voltage between first electrode 30 and nozzle26 and the magnitude of the voltage, for example.

Control unit 72 is implemented by a microcontroller, for example.Specifically, control unit 72 is implemented by a nonvolatile memorystoring a program, a volatile memory used as a temporary storage areafor execution of the program, an input/output port, a processor thatexecutes the program, and the like. Control unit 72 may be implementedby a dedicated electronic circuit that realizes each operation.

Note that control unit 72 has only to be able to control voltageapplying unit 40 and supplying units 211, 212, and 213, and may controlvoltage applying unit 40 and supplying units 211, 212, and 213 bytransmitting a radio signal or may be connected to voltage applying unit40 and supplying units 211, 212, and 213 by a control line or the like.

As described above, unlike mist-generating device 100 according toEmbodiment 1, mist-generating device 100 b does not include supplyingunit 210, and third liquid L3 containing functional droplet L issupplied from droplet generating unit 300 to mist-generating unit 400.In other words, mist-generating device 100 b includes droplet generatingunit 300 that generates functional droplet L in third liquid L3,functional droplet L containing first liquid L1 that has a sphericalshape and second liquid L2 that has a lower volatility than first liquidL1 and covers the whole of first liquid L1, and mist-generating unit 400that generates multilayer mist M by atomizing third liquid L3 containingfunctional droplet L.

With such a configuration, third liquid L3 containing functional dropletL can be generated with an even simpler configuration, and multilayermist M can be generated by atomizing generated third liquid L3containing functional droplet L.

Embodiment 2

In the following, a mist-generating device according to Embodiment 2will be described.

[Configuration]

<Overview>

First, with reference to FIGS. 11 to 15, an overview of multilayer mistBM and a configuration of a mist-generating device that generatesmultilayer mist BM will be described.

FIG. 11 is a schematic cross-sectional view showing a configuration ofmist-generating device B100 according to Embodiment 2.

As shown in FIG. 11, mist-generating device B100 according to Embodiment2 includes container B10, ejection plate B20, first electrode B30,voltage applying unit B40, supplying unit B300, and control unit B70.Ejection plate B20 includes electrode support plate B21 and nozzle B26.

FIG. 11 shows control unit B70 as a functional block. Control unit B70is implemented by a microcomputer (microcontroller), for example, and isarranged inside an outer housing (not shown) of mist-generating deviceB100. Control unit B70 may be attached to the exterior of container B10,for example.

Mist-generating device B100 is a spray device that ejects multilayermist BM capable of floating in the air formed by atomizing first liquidL1 and second liquid L2. For example, mist-generating device B100 is adevice that generates multilayer mist BM having a disinfection effect orsanitization effect by applying a high voltage to first liquid L1 andsecond liquid L2 to produce an electrostatic force and atomizing firstliquid L1 and second liquid L2 by the action of the producedelectrostatic force. “Multilayer mist BM” refers to a mist formed byatomizing first liquid L1 and second liquid L2 or one of a plurality ofliquid particles forming the mist. Mist-generating device B100 is usedfor a disinfecting device or a sanitizing device, for example.

Note that when first liquid L1 contains an aromatic constituent, forexample, mist-generating device B100 is an aroma generator thatgenerates multilayer mist BM containing an aromatic constituent.

In mist-generating device B100, supplying unit B300 feeds first liquidL1 and second liquid L2 in container B10 to nozzle B26 to introducefirst liquid L1 and second liquid L2 to a tip end of nozzle B26, and alarge number of multilayer mists BM formed by atomizing first liquid L1and second liquid L2 are ejected from opening B29 provided at the tipend of nozzle B26.

Specifically, voltage applying unit B40 applies a high voltage betweenfirst electrode B30 and nozzle B26, which is an example of a secondelectrode, thereby causing ejection of a mist of first liquid L1 andsecond liquid L2 (that is, a large number of multilayer mists BM) fromopening B29 of nozzle B26. Here, the “high voltage” is on the order of 5kV with respect to a ground voltage (0 V), for example, but is notparticularly limited. Note that the voltage of first electrode B30 maybe positive or negative with respect to the ground voltage.

A channel that introduces first liquid L1 and second liquid L2 toopening B29 in container 10 is formed in nozzle B26. First liquid L1 andsecond liquid L2 having flowed in the channel and exited opening B29 arechanged in shape by the electric field to form a Taylor cone. Firstliquid L1 and second liquid L2 are atomized at the tip end of the Taylorcone to form multilayer mist BM.

Note that, although FIG. 11 shows one nozzle B26, the number of nozzlesB26 provided on ejection plate B20 is not particularly limited and maybe two, or three or more.

Multilayer mist BM generated at the tip end of nozzle B26 is dischargedtoward first electrode B30. In order to discharge multilayer mist BM inthe forward direction beyond first electrode B30, through-hole B32 isformed in flat plate part B31 of first electrode B30 at a positiondirectly opposed to nozzle B26. This allows multilayer mist BM to bedischarged through through-hole B32 in the forward direction beyondfirst electrode B30. Here, the “forward direction” refers to a directionin which multilayer mist BM is discharged and is the opposite directionto nozzle B26 with respect to first electrode B30.

FIG. 12 is a cross-sectional view showing a configuration of multilayermist BM according to Embodiment 2.

Multilayer mist BM is a fine liquid particle having a diameter of theorder of nanometers or micrometers, and is capable of floating in theair. For example, the outer diameter of multilayer mist BM is on theorder of several tens of μm. Note that the outer diameter of multilayermist BM is preferably equal to or smaller than 10 μm. More preferably,the diameter of a liquid particle forming multilayer mist BM is equal toor greater than 10 nm and equal to or smaller than 3 μm.

Multilayer mist BM contains first liquid L1 that has a spherical shapeand second liquid L2 that has a film-like shape and covers the whole offirst liquid L1.

First liquid L1 is a liquid particle that has a predetermined function(effect). For example, first liquid L1 is a liquid particle containingan aromatic constituent that has a function of generating an aroma whencoming into contact with air, or a liquid particle that has a functionof killing a target such as a fungus when coming into contact with thetarget.

Second liquid L2 is a liquid having a film-like shape that has a lowervolatility than first liquid L1 and covers the whole of first liquid L1.In other words, second liquid L2 is a liquid that covers the whole offirst liquid L1 and is less susceptible to volatilization than firstliquid L1. That is, the volatility of second liquid L2 is lower than thevolatility of first liquid L1. Second liquid L2 is formed in a film-likeshape to cover the whole of first liquid L1.

Second liquid L2 is formed to have a thickness that allows second liquidL2 to volatilize or be lost before multilayer mist BM reaches to apredetermined distance from the location where the mist is generated(that is, mist-generating device B100) so that first liquid L1 isexposed and comes into contact with air. Specifically, second liquid L2is formed to have a thickness that allows second liquid L2 to volatilizeor be lost to allow first liquid L1 to be exposed and come into contactwith air when a predetermined time has elapsed or, in other words, whenmultilayer mist BM generated by mist-generating device B100 has moved apredetermined distance. The predetermined distance can be arbitrarilydetermined. The thickness of second liquid L2 of multilayer mist BM canbe any thickness as far as second liquid L2 completely volatilizes whena predetermined time, which is arbitrarily determined in advance, haselapsed or, in other words, when multilayer mist BM has moved thepredetermined distance. For example, the thickness of second liquid L2of multilayer mist BM can be approximately equal to the radius of firstliquid L1 of multilayer mist BM, greater than the radius of first liquidL1, or smaller than the radius of first liquid L1.

In order to prevent mixing of first liquid L1 and second liquid L2 inmultilayer mist BM, for example, one of first liquid L1 and secondliquid L2 is oily, and the other is aqueous. That is, one of firstliquid L1 and second liquid L2 is oily, and the other is aqueous.

In the following, each component of mist-generating device B100 will bedescribed in detail.

<Container>

Container B10 is a container that accommodates first liquid L1 andsecond liquid L2. Container B10 includes first accommodation unit B11that accommodates first liquid L1 and second accommodation unit B12 thataccommodates second liquid L2.

First accommodation unit B11 is a space that accommodates first liquidL1. First liquid L1 is a liquid that delivers a predetermined functionwhen coming into contact with air, for example. When mist-generatingdevice B100 is an aroma generator, for example, first liquid L1 is anoily liquid containing an aromatic constituent. When mist-generatingdevice B100 is a disinfecting device, for example, first liquid L1 is anaqueous liquid containing a disinfection constituent such ashypochlorous acid. Note that, when first liquid L1 and second liquid L2are atomized in an electrostatic atomization process as in thisembodiment, first liquid L1 may be water.

Second accommodation unit B12 is a space that accommodates second liquidL2. When first liquid L1 is an oily liquid containing an aromaticconstituent, for example, second liquid L2 is an aqueous liquid having alower volatility than first liquid L1. When first liquid L1 is anaqueous liquid containing a disinfection constituent such ashypochlorous acid, for example, second liquid L2 is an oily liquid.Second liquid L2 is formed in a film-like shape.

For example, second liquid L2 has a lower volatility than first liquidL1. That is, second liquid L2 may be a material that is less susceptibleto volatilization than first liquid L1.

Container B10 is made of a metal material such as stainless steel, forexample. However, container B10 may be made of a resin material.Container B10 may be made of a material having one or both of acidresistance and alkali resistance.

Container B10 has the shape of a cylinder with an open top, for example.However, the shape of container B10 is not limited thereto. ContainerB10 may have the shape of a cube, a rectangular parallelepiped, or aflat tray. The open top of container B10 is covered by ejection plateB20.

<Ejection Plate>

FIG. 13 is a schematic perspective view of nozzle B26 according toEmbodiment 2. FIG. 14 is a partial enlarged cross-sectional view showinga cross section of nozzle B26 taken along the line XIV-XIV in FIG. 13.

Ejection plate B20 has opening B29 through which first liquid L1 andsecond liquid L2 are ejected. Specifically, ejection plate B20 includeselectrode support plate B21 having a planar shape, and nozzle B26. Firstdischarging port B29 a and second discharging port B29 b of opening B29are provided at a tip end of nozzle B26. More specifically, as shown inFIG. 13, nozzle B26 has inner first discharging port B29 a and outersecond discharging port B29 b that are concentrically formed. In FIG.13, nozzle B26 has inner first discharging port B29 a and outer seconddischarging port B29 b that are concentrically formed.

As shown in FIG. 14, first liquid L1 is discharged from firstdischarging port B29 a of nozzle B26 through first channel B25 a. Secondliquid L2 is discharged from second discharging port B29 b of nozzle B26through second channel B25 b in such a manner as to cover first liquidL1 discharged from first discharging port B29 a. In this way,mist-generating device B100 generates multilayer mist BM containingfirst liquid L1 having a spherical shape and second liquid L2 having afilm-like shape covering the whole of first liquid L1.

Electrode support plate B21 is a plate-like member that supports nozzleB26. Electrode support plate B21 is made of a resin material, forexample. However, electrode support plate B21 may be made of a metalmaterial. Electrode support plate B21 may be made of a material havingone or both of acid resistance and alkali resistance.

Nozzle B26 is fixed to electrode support plate B21 by press-fitting. Forexample, a through-hole is formed in electrode support plate B21 at alocation where opening B29 is to be provided, and nozzle B26 is insertedinto the through-hole and fixed. Electrode support plate B21 is a flatplate having a uniform thickness. However, the present invention is notthereto, and electrode support plate B21 may be a curved plate.

Electrode support plate B21 is fixed to container B10. Note thatelectrode support plate B21 may be made of the same material ascontainer B10 and formed integrally with container B10.

Nozzle B26 is connected to container B10 and discharges first liquid L1and second liquid L2 in container B10 to the outside of container B10.Specifically, nozzle B26 is connected to first accommodation unit B11and second accommodation unit B12 by first channel B25 a and secondchannel B25 b. Nozzle B26 discharges first liquid L1 in firstaccommodation unit B11 from first discharging port B29 a through firstchannel B25 a, and discharges second liquid L2 in second accommodationunit B12 from second discharging port B29 b through second channel B25b. Nozzle B26 projects toward first electrode B30 from electrode supportplate B21. Nozzle B26 has an opening at a rear end thereof (that is, anend on the side of container B10), and a channel extending from theopening to opening B29.

Note that at least one of the inner and outer diameters of nozzle B26may be tapered from the rear end toward the tip end. For example,opening B29 at the tip end may be smaller than the opening at the rearend, and the channel connecting these openings may have the shape of atruncated cone. Here, note that the inner diameter (bore diameter) offirst discharging port B29 a and the inner diameter (bore diameter) ofsecond discharging port B29 b are the inner diameters (bore diameters)of first nozzle part B27 and second nozzle part B28 at the rear endcloser to first electrode B30.

The rear end of nozzle B26 is positioned at a location where the rearend is in contact with first liquid L1 and second liquid L2 in containerB10. Specifically, the rear end of nozzle B26 is located in such amanner that the channels formed in nozzle B26 are in communication withthe interiors of first accommodation unit B11 and second accommodationunit B12.

As shown in FIGS. 13 and 14, first supplying unit B310 introduces firstliquid L1 from the opening at the rear end of nozzle B26 to firstdischarging port B29 a at the tip end through first channel B25 a innozzle B26. Second supplying unit B320 introduces second liquid L2 fromthe opening at the rear end of nozzle B26 to second discharging port B29b at the tip end through second channel B25 b.

Nozzle B26 stands perpendicularly to a principal surface (specifically,an upper surface) of electrode support plate B21. The principal surfaceis a surface of electrode support plate B21 that is opposed to firstelectrode B30 and is on the opposite side to first liquid L1 and secondliquid L2. The ratio of height to outer diameter (referred to as anaspect ratio, hereinafter) of nozzle B26 is preferably equal to orgreater than 4. Here, the height of nozzle B26 is represented by thedistance from the tip end of nozzle B26 to the principal surface ofelectrode support plate B21. The height is equal to or greater than 2mm, for example. The greater the aspect ratio of nozzle B26, the moreeasily the electric field is concentrated at the tip end of nozzle B26.Therefore, the aspect ratio of nozzle B26 can be equal to or greaterthan 6, for example.

The material of nozzle B26 is not particularly limited. For example,nozzle B26 may be a metal material having a conductivity, such asstainless steel. For example, if first nozzle part B27 is made of aconductive material, first nozzle part B27 can serve as a secondelectrode paired with first electrode B30. That is, at least a part offirst nozzle part B27 may be formed as a second electrode paired withfirst electrode B30. The second electrode (nozzle B26 in thisembodiment) is paired with first electrode B30, and a voltage is appliedto at least one of first liquid L1 and second liquid L2 discharged fromnozzle B26 to produce multilayer mist BM.

Second nozzle part B28 may be made of a metal material having aconductivity, such as stainless steel, or may be made of a materialhaving insulation properties, such as resin.

Note that mist-generating device B100 may be provided with an electrodehoused in each of first accommodation unit B11 and second accommodationunit B12 and paired with first electrode B30, as a second electrode, forexample. In that case, first nozzle part B27 may be made of a materialhaving insulation properties, such as resin. First nozzle part B27 maybe made of a material having one or both of acid resistance and alkaliresistance.

Voltage applying unit B40 may be electrically connected to second nozzlepart B28. With such a configuration, a voltage can be more easilyapplied to second liquid L2. In that case, second nozzle part B28 can bemade of a conductive material.

<First Electrode>

First electrode B30 is an opposed electrode that is arranged outsidecontainer B10 in such a manner that through-hole B32 is opposed toopening B29. Specifically, first electrode B30 is arranged outsidecontainer B10 to be opposed to nozzle B26 serving also as a secondelectrode paired with first electrode B30. When a voltage is appliedbetween first electrode B30 and nozzle B26, first liquid L1 and secondliquid L2 are discharged from the tip end of nozzle B26 and atomized.First electrode B30 is arranged in parallel with electrode support plateB21 of ejection plate B20, for example. Specifically, a rear surface offirst electrode B30 is in parallel with the principal surface ofelectrode support plate B21.

First electrode B30 is made of a metal material having a conductivity,such as stainless steel. First electrode B30 may be made of a materialhaving one or both of acid resistance and alkali resistance.

First electrode B30 includes flat plate part B31 and through-hole B32.Flat plate part B31 is conductive and is electrically connected tovoltage applying unit B40. Flat plate part B31 has a substantiallyuniform thickness. Nozzle B26 (more specifically, first nozzle part B27)is also conductive and is electrically connected to voltage applyingunit B40.

Through-hole B32 passes through flat plate part B31 in the thicknessdirection (that is, the back-and-forth direction). Through-hole B32 isprovided to allow atomized first liquid L1 and second liquid L2 ejectedfrom opening B29, that is, multilayer mist BM, to pass through flatplate part B31. Through-hole B32 has a flat cylindrical shape. The shapeof the opening of through-hole B32 is not limited to a circle but can bea square, a rectangle, or an ellipse, for example.

The diameter of the opening of through-hole B32 is not particularlylimited. For example, the diameter falls within a range from 1 mm to2.25 mm inclusive. The diameter of the opening of through-hole B32 maybe five or more times greater than and ten or less times smaller thanthe outer diameter of nozzle B26. Multilayer mist BM discharged from thetip end of the Taylor cone spreads in a conical shape. Therefore, thegreater the diameter of the opening of through-hole B32, the moremultilayer mist BM passes through through-hole B32.

<Voltage Applying Unit>

Voltage applying unit B40 applies a predetermined voltage between firstliquid L1 and second liquid L2 and first electrode B30. Specifically,voltage applying unit B40 is electrically connected to first electrodeB30 and nozzle B26 (more specifically, first nozzle part B27) by metalwiring or the like, and applies a voltage so as to produce apredetermined potential difference between first electrode B30 and firstnozzle part B27. For example, first nozzle part B27 is grounded, andvoltage applying unit B40 applies the ground potential to first liquidL1 and second liquid L2. Voltage applying unit B40 applies a potentialto first electrode B30, thereby applying a predetermined voltage betweenfirst electrode B30 and first liquid L1 and second liquid L2. Note thatfirst electrode B30 may be at the ground potential.

The predetermined voltage applied by voltage applying unit B40 is adirect-current voltage equal to or higher than 3.5 kV and equal to orlower than 10 kV. Alternatively, the predetermined voltage may be equalto or higher than 4.5 kV and equal to or lower than 8.5 kV. Note thatthe predetermined voltage may be a pulse voltage, a pulsating voltage,or an alternating-current voltage.

Specifically, voltage applying unit B40 is implemented by a power supplycircuit including a converter or the like. For example, voltage applyingunit B40 applies a voltage to first liquid L1 and second liquid L2 bygenerating a predetermined voltage based on an electric power receivedfrom an external power supply, such as a utility power supply, andapplying the generated voltage between first electrode B30 and thesecond electrode.

<Supplying Unit>

Supplying unit B300 feeds first liquid L1 and second liquid L2 incontainer B10 to nozzle B26. Supplying unit B300 includes firstsupplying unit B310 and second supplying unit B320, for example.

First supplying unit B310 supplies first liquid L1 to first dischargingport B29 a through first channel B25 a formed in nozzle B26.Specifically, first supplying unit B310 is a pump that feeds firstliquid L1 in first accommodation unit B11 to first discharging port B29a through first channel B25 a formed in nozzle B26 (specifically, firstnozzle part B27).

Second supplying unit B320 supplies second liquid L2 to seconddischarging port B29 b through second channel B25 b formed in nozzleB26. Specifically, second supplying unit B320 is a pump that feedssecond liquid L2 in second accommodation unit B12 to second dischargingport B29 b through second channel B25 b formed in nozzle B26, or morespecifically, defined by an outer side surface of first nozzle part B27and an inner side surface of second nozzle part B28.

<Control Unit>

Control unit B70 is a controlling device that controls the overalloperation of mist-generating device B100. Specifically, control unit B70controls operations of voltage applying unit B40 and supplying unitB300. For example, control unit B70 controls voltage applying unit B40,thereby controlling the timing of application of a voltage between firstelectrode B30 and nozzle B26 and the magnitude of the voltage, forexample.

FIG. 15 is a schematic cross-sectional view schematically showing howmultilayer mist BM is generated by mist-generating device B100 accordingto Embodiment 2.

As shown in FIGS. 14 and 15, control unit B70 controls supplying unitB300 and voltage applying unit B40 to discharge first liquid L1 fromfirst discharging port B29 a and discharge second liquid L2 having alower volatility than first liquid L1 from second discharging port B29b, thereby generating multilayer mist BM containing first liquid L1having a spherical shape and second liquid L2 having a film-like shapecovering the whole of first liquid L1.

If control unit B70 appropriately controls first supplying unit B310 andvoltage applying unit B40, first liquid L1 discharged from nozzle B26forms a neat Taylor cone. This means that the amount of first liquid L1fed to nozzle B26 is appropriate. Similarly, if control unit B70appropriately controls second supplying unit B320 and voltage applyingunit B40, second liquid L2 discharged from nozzle B26 forms a neatTaylor cone. Control unit B70 controls supplying unit B300 toappropriately control the amounts of first liquid L1 and second liquidL2 fed by supplying unit B300.

Control unit B70 also controls the thickness of second liquid L2 inmultilayer mist BM by controlling the amount of first liquid L1 suppliedby supplying unit B300 (specifically, first supplying unit B310), forexample. Specifically, control unit B70 controls the thickness of secondliquid L2 in multilayer mist BM by controlling at least one of theamount of first liquid L1 supplied by first supplying unit B310 and theamount of second liquid L2 supplied by second supplying unit B320.

Control unit B70 is implemented by a microcontroller, for example.Specifically, control unit B70 is implemented by a nonvolatile memorystoring a program, a volatile memory used as a temporary storage areafor execution of the program, an input/output port, a processor thatexecutes the program, and the like. Control unit B70 may be implementedby a dedicated electronic circuit that realizes each operation.

Note that control unit B70 has only to be able to control voltageapplying unit B40 and supplying unit B300, and may control voltageapplying unit B40 and supplying unit B300 by transmitting a radio signalor may be connected to voltage applying unit B40 and supplying unit B300by a control line or the like.

[Effects and the Like]

As described above, multilayer mist BM according to Embodiment 2 is afloatable functional particle capable of floating in the air. Multilayermist BM contains first liquid L1 having a spherical shape that has apredetermined function, and second liquid L2 having a film-like shapethat has a lower volatility than first liquid L1 and covers the whole offirst liquid L1.

FIG. 16 is a schematic diagram for illustrating an effect of multilayermist BM according to Embodiment 2.

As shown in FIG. 16, with a conventional nanomist according tocomparative example 1, a functional droplet that delivers a functionwhen coming into contact with air is exposed and therefore immediatelyvaporizes after the functional droplet is discharged into the air.

A conventional mist according to comparative example 2 has a largeparticle diameter of the order of several hundreds of μm in order toprevent immediate vaporization of the mist. However, the mist falls soonunder its own weight and cannot travel far.

Multilayer mist BM has a structure in which first liquid L1 thatdelivers a function when coming into contact with air is covered bysecond liquid L2.

With multilayer mist BM thus configured, second liquid L2 firstvaporizes, and first liquid L1 then vaporizes. Therefore, if thethickness of second liquid L2 is appropriately adjusted, multilayer mistBM is likely to be able to float in the air for a desired floating time.In this way, the floating time of multilayer mist BM in the air can beextended compared with conventional mists.

For example, one of first liquid L1 and second liquid L2 is oily, andthe other is aqueous.

With such a configuration, first liquid L1 and second liquid L2 areunlikely to be mixed. Therefore, with such a configuration, the floatingtime of multilayer mist BM in the air can be further extended.

For example, the particle diameter of multilayer mist BM is equal to orsmaller than 10 μm. According to the prediction by the presentinventors, when the particle diameter of multilayer mist BM is 5 μm, forexample, the floating time of multilayer mist BM in the air is about 20minutes. Furthermore, according to the prediction by the presentinventors, when the particle diameter of multilayer mist BM is 3 μm, forexample, the floating time of multilayer mist BM in the air is about 60minutes. Furthermore, according to the prediction by the presentinventors, when the particle diameter of multilayer mist BM is 1 μm, forexample, the floating time of multilayer mist BM in the air is about 550minutes. Here, the thickness of the film of second liquid L2 is reducedas the particle diameter of multilayer mist BM decreases. For example,the thickness of the film of second liquid L2 is equal to or smallerthan 80 nm when the particle diameter of multilayer mist BM is 5 μm, isequal to or smaller than 50 nm when the particle diameter of multilayermist BM is 3 μm, and is equal to or smaller than 15 nm when the particlediameter of multilayer mist BM is 1 μm. If the floating time ofmultilayer mist BM in the air can be extended in this way, a largernumber of multilayer mists BM are likely to come into contact with thesurface of a person in the living space of the person. Therefore, ifmultilayer mist BM has the sizes described above, the chances can beincreased that multilayer mist BM comes into contact with the surface ofa human body, and second liquid L2 disappears, that is, multilayer mistBM comes into contact with the surface of a human body, and first liquidL1 having been covered by second liquid L2 is exposed, and as a result,first liquid L1 becomes able to exert its effect, such as disinfectioneffect, on the human body (the face, in particular).

If multilayer mist BM has the sizes described above, multilayer mist BMdoes not fall soon under its own weight and can float in the air for anextended time.

Furthermore, mist-generating device B100 according to Embodiment 2includes nozzle B26 having inner first discharging port B29 a and outersecond discharging port B29 b that are concentrically formed, andcontrol unit B70 that controls first discharging port B29 a to dischargefirst liquid L1 and second discharging port B29 b to discharge secondliquid L2 having a lower volatility than first liquid L1 so as togenerate multilayer mist BM floating in the air that contains firstliquid L1 having a spherical shape and second liquid L2 covering thewhole of first liquid L1.

With such a configuration, mist-generating device B100 can generatemultilayer mist BM having a longer floating time in the air thanconventional described above.

Furthermore, mist-generating device B100 includes first supplying unitB310 that supplies first liquid L1 to first discharging port B29 athrough first channel B25 a formed in nozzle B26, and second supplyingunit B320 that supplies second liquid L2 to second discharging port B29b through second channel B25 b,which is different from first channel B25a, that is formed in nozzle B26. Control unit B70 further controls thethickness of second liquid L2 (that is, second liquid L2) in multilayermist BM by controlling at least one of the amount of first liquid L1supplied by first supplying unit B310 and the amount of second liquid L2supplied by second supplying unit B320.

With such a configuration, mist-generating device B100 can generatemultilayer mist BM containing second liquid L2 having a variablethickness under the control of control unit B70. Therefore, with such aconfiguration, mist-generating device B100 can generate multilayer mistBM having a dwell time in the air that is appropriate to the size of thespace in which mist-generating device B100 is installed.

Mist-generating device B100 further includes first electrode B30arranged to be opposed to nozzle B26, and a second electrode paired withfirst electrode B30 that applies a voltage to at least one of firstliquid L1 and second liquid L2 discharged from nozzle B26 to generatemultilayer mist BM, for example.

With such a configuration, mist-generating device B100 can simplygenerate multilayer mist BM having a particle diameter of the order ofnanometers to micrometers.

In mist-generating device B100, at least part of first nozzle part B27is formed as a second electrode.

With such a configuration, mist-generating device B100 can generatemultilayer mist BM with a simpler configuration without a separatemember serving as a second electrode.

(Variation 1)

FIG. 17 is a schematic cross-sectional view showing a configuration ofnozzle B26 a of a mist-generating device according to Variation 1 ofEmbodiment 2.

Note that the mist-generating device according to Variation 1 ofEmbodiment 2 has the same components as those of mist-generating deviceB100 according to Embodiment 2 except for the nozzle thereof. Referringto FIG. 8, the components of the mist-generating device according toVariation 1 of Embodiment 2 that are substantially the same as those ofmist-generating device B100 according to Embodiment 2 are denoted by thesame reference numerals, and descriptions thereof will be simplified oromitted.

As shown in FIG. 17, nozzle B26 a includes first nozzle part B27 a andsecond nozzle part B28. Specifically, nozzle B26 a includes first nozzlepart B27 a that has first discharging port B29 a, and second nozzle partB28 that covers an outer side surface of first nozzle part B27 a at adistance in the radial direction to define second discharging port B29 bwith first nozzle part B27 a. Here, nozzle B26 a differs from nozzle B26in that the end part of first nozzle part B27 a in which firstdischarging port B29 a is formed is retracted from end part B29 c ofsecond nozzle part B28.

For example, second liquid L2 may be difficult to form a Taylor conelike that of first liquid L1, depending on the material. In such a case,if the end part of first nozzle part B27 a in which first dischargingport B29 a is formed is retracted from end part B29 c of second nozzlepart B28 as shown in FIG. 17, multilayer mist BM containing a film ofsecond liquid L2 having a desired thickness (see FIG. 12) can begenerated as with mist-generating device 100 according to Embodiment 2shown in FIG. 15.

As described above, for example, nozzle B26 a of the mist-generatingdevice according to Variation 1 of Embodiment 2 includes first nozzlepart B27 a that has first discharging port B29 a, and second nozzle partB28 that covers an outer side surface of first nozzle part B27 a at adistance in the radial direction to define second discharging port B29 bwith first nozzle part B27 a. The end part of first nozzle part B27 a inwhich first discharging port B29 a is formed is retracted from end partB29 c of second nozzle part B28.

With such a configuration, even when second liquid L2 is difficult toform a Taylor cone like that of first liquid L1, for example, multilayermist BM containing a film of second liquid L2 having a desired thicknesscan be generated.

(Variation 2)

FIG. 18 is a schematic cross-sectional view showing a configuration of anozzle of a mist-generating device according to Variation 2 ofEmbodiment 2.

Note that the mist-generating device according to Variation 2 ofEmbodiment 2 has the same components as those of mist-generating deviceB100 according to Embodiment 2 except for the nozzle thereof. Referringto FIG. 18, the components of the mist-generating device according toVariation 2 of Embodiment 2 that are substantially the same as those ofmist-generating device B100 according to Embodiment 2 are denoted by thesame reference numerals, and descriptions thereof will be simplified oromitted.

As shown in FIG. 18, the mist-generating device according to Variation 2of Embodiment 2 has nozzle B26 and nozzle B26 b. That is, themist-generating device according to Variation 2 of Embodiment 2 has aplurality of nozzles.

Nozzle B26 b is a nozzle for generating multilayer mist BM1 containingsecond liquid L2 having a different thickness than second liquid L2 ofmultilayer mist BM. Second discharging port B29 b of nozzle B26 andsecond discharging port B29 bb of nozzle B26 b have different borediameters. Specifically, the plurality of nozzles B26 and B26 b havefirst discharging port B29 a having the same bore diameter, that is,have the first nozzle part having the same outer diameter, but theplurality of nozzles B26 and B26 b have second discharging ports B29 band B29 bb having different bore diameters R1 and R2, respectively. FIG.18 illustrates a case where bore diameter R1 of second discharging portB29 b of nozzle B26 is smaller than bore diameter R2 of seconddischarging port B29 bb of nozzle B26 b.

Although not shown, first discharging port B29 a of nozzle B26 b is incommunication with first accommodation unit B11 via the channel innozzle B26 so that first liquid L1 can move therebetween. Seconddischarging port B29 bb of nozzle B26 b is in communication with secondaccommodation unit B12 via the channel in nozzle B26 so that secondliquid L2 can move therebetween.

Unlike first electrode B30, a plurality of through-holes B32 are formedin first electrode B30 a. The plurality of through-holes B32 passthrough flat plate part B31 in the thickness direction (that is, theback-and-forth direction). The plurality of through-holes B32 are formedat locations opposed to nozzles B26 and B26 b.

FIG. 18 shows two nozzles B26 and B26 b. The same number ofthrough-holes B32 as the plurality of nozzles are formed in flat platepart B31.

As described above, the mist-generating device according to Variation 2of Embodiment 2 has a plurality of nozzles. The plurality of nozzles(nozzles B26 and B26 b, for example) have second discharging ports ofdifferent bore diameters (bore diameters R1 and R2, for example).

With such a configuration, provided that the first nozzle parts have thesame outer diameter, the mist-generating device according to Variation 2of Embodiment 2 can generate a plurality of multilayer mists eachcontaining a film of second liquid L2 having a different thickness(multilayer mists BM and BM1 shown in FIG. 9, for example) at the sametime. That is, the mist-generating device according to Variation 2 ofEmbodiment 2 can generate a plurality of multilayer mists BM and BM1that can float in the air for different lengths of time at the sametime. Therefore, the mist-generating device according to Variation 2 ofEmbodiment 2 is likely to uniformly generate multilayer mists BM and BM1in a predetermined space.

Note that, in the mist-generating device according to Embodiment 2, forexample, first accommodation unit B11 may accommodate third liquid L3containing functional droplet L generated by mist-generating unit 400shown in FIG. 1, and second accommodation unit B12 may accommodate afourth liquid that differs from third liquid L3 in liquid properties(oily or aqueous). In other words, one of third liquid L3 and the fourthliquid is oily, and the other is aqueous.

For example, the mist-generating device includes nozzle B26 thatdischarges third liquid L3 containing functional droplet L, and firstelectrode B30 that is arranged to be opposed to nozzle B26 and applies avoltage to third liquid L3 containing functional droplet L dischargedfrom nozzle B26 to atomize third liquid L3 containing functional dropletL to generate a multilayer mist. Nozzle B26 may have inner firstdischarging port B29 a and outer second discharging port B29 b that areconcentrically formed, and the control unit may control firstdischarging port B29 a to discharge third liquid L3 containingfunctional droplet L and second discharging port B29 b to discharge afourth liquid having a lower volatility than third liquid L3 so as togenerate a multilayer mist containing third liquid L3 having a sphericalshape and the fourth liquid covering the whole of third liquid L3.

With such a configuration, the mist-generating device can more simplygenerate a multilayer mist containing a plurality of liquid layers.

Embodiment 3

In the following, a mist-generating device according to Embodiment 3will be described. The description of the mist-generating deviceaccording to Embodiment 3 will be focused on differences frommist-generating device 100 according to Embodiment 1. In the descriptionof the mist-generating device according to Embodiment 3, the componentsthat are substantially the same as those of mist-generating device 100according to Embodiment 1 are denoted by the same reference numerals,and descriptions thereof may be simplified or omitted.

FIG. 19 is a schematic perspective view showing a configuration ofmist-generating device 100 c according to Embodiment 3.

As shown in FIG. 19, mist-generating device 100 c includes dropletgenerating unit 300 c and mist-generating unit 402.

Droplet generating unit 300 c includes microchannel chip 302, which is amicrofluidic device that has a channel having a size of the order ofmicrometers and generates functional droplet L in third liquid L3, andsupplying units 211, 212, and 213 that supply first liquid L1, secondliquid L2, and third liquid L3 to microchannel chip 302.

Microchannel chip 302 is a plate-like body in which a channel is formedthrough which first liquid L1, second liquid L2, and third liquid L3pass. The channel of microchannel chip 302 branches in a T-shaped and/orX-shaped configuration. In this embodiment, as with microchannel chip301 shown in FIG. 4, microchannel chip 302 has first liquid channel 311(see FIG. 4) through which first liquid L1 passes, second liquid channel321 (see FIG. 4) through which second liquid L2 passes, mixing channel322 (see FIG. 4) that is connected to first liquid channel 311 andsecond liquid channel 321 and allows the whole of first liquid L1 to becovered by second liquid L2, and third liquid channel 331 (see FIG. 4)that is connected to mixing channel 322 and allows the whole of firstliquid L1 and second liquid L2 to be covered by third liquid L3.Microchannel chip 302 has discharging port 600 that is connected tothird liquid channel 331 and discharges third liquid L3 containingfunctional droplet L having passed through third liquid channel 331 tothe outside of microchannel chip 302.

Discharging port 600 is a hole formed in microchannel chip 302 fordischarging third liquid L3 containing functional droplet L havingpassed through third liquid channel 331 to the outside of microchannelchip 302.

In this embodiment, microchannel chip 302 is a plate-like body, anddischarging port 600 is formed in a side surface (discharging surface620) of microchannel chip 302. Discharge liquid 610, which is thirdliquid L3 containing functional droplet L, is discharged fromdischarging port 600.

Microchannel chip 302 is made of a glass material or a resin material,for example.

Discharging surface 620 of microchannel chip 302 has a water repellency,for example.

Therefore, discharge liquid 610 is difficult to adhere to dischargingsurface 620. As a result, discharge liquid 610 is likely to spurt fromdischarging port 600, rather than dripping.

Mist-generating unit 402 is a device that generates multilayer mist M byatomizing third liquid L3 containing functional droplet L generated bymicrochannel chip 302. In this embodiment, mist-generating unit 402 isan air blower that blows air.

For example, mist-generating unit 402 blows air vertically upward.Microchannel chip 302 is arranged above mist-generating unit 402 in thevertical direction, and horizontally discharges discharge liquid 610from discharging port 600 to directly above mist-generating unit 402.

FIG. 20 is a diagram schematically showing how multilayer mist M isgenerated by mist-generating device 100 c according to Embodiment 3.

As for the setting of the pressure under which discharge liquid 610 ishorizontally discharged from discharging port 600, control unit 73 setsthe discharge pressure so that discharged third liquid L3 containingfunctional droplet L forms a liquid column by controlling the amount offirst liquid L1, second liquid L2, and/or third liquid L3 supplied perunit time to microchannel chip 302 by supplying unit 211, 212, and/or213.

The liquid column becomes slightly constricted in parts betweenparticles of second liquid L2, which has a relatively low volatility anda relatively high viscosity.

The liquid column becomes further constricted because of the surfacetension and eventually splits into a plurality of parts, and thirdliquid L3 volatilizes. In this way, multilayer mist M with second liquidL2 exposed to the air is formed.

To promote the splitting of such fine liquid columns, mist-generatingunit 402 blows air from below to discharge liquid 610 forming the liquidcolumns. Thus, the efficiency of the atomization of discharge liquid 610can be increased. In addition, multilayer mist M is discharged upward ina controlled manner by the action of the blown air, so that the floatingtime of multilayer mist M can be extended.

Control unit 73 is a control device that controls the overall operationof mist-generating device 100 c. Specifically, control unit 73 controlsoperations of mist-generating unit 402 and supplying units 211, 212, and213, for example. For example, control unit 73 controls mist-generatingunit 402, thereby controlling the timing of air-blow of mist-generatingunit 402 and the magnitude of the wind, for example.

Control unit 73 is implemented by a microcontroller, for example.Specifically, control unit 73 is implemented by a nonvolatile memorystoring a program, a volatile memory used as a temporary storage areafor execution of the program, an input/output port, a processor thatexecutes the program, and the like. Control unit 73 may be implementedby a dedicated electronic circuit that realizes each operation.

Note that control unit 73 has only to be able to control mist-generatingunit 402 and supplying units 211, 212, and 213, and may controlmist-generating unit 402 and supplying units 211, 212, and 213 bytransmitting a radio signal or may be connected to mist-generating unit402 and supplying units 211, 212, and 213 by a control line or the like.

Note that microchannel chip 302 shown in FIG. 19 does not have reservoir340 shown in FIG. 4. When a mist-generating unit atomizes third liquidL3 containing functional droplet L by electrostatic atomization orultrasonic vibration, an amount of third liquid L3 containing functionaldroplet L equal to or greater than the predetermined amount is needed.However, mist-generating device 100 c generates multilayer mist M byatomizing third liquid L3 containing functional droplet L by blowing airto discharge liquid 610 discharged from microchannel chip 302, andtherefore can atomize a small amount of third liquid L3 containingfunctional droplet L. Therefore, any accommodation unit thataccommodates third liquid L3 containing functional droplet L, such asreservoir 340 shown in FIG. 4, can be omitted. Therefore, microchannelchip 302 can be reduced in size. In addition, by using microchannel chip302, each single particle of multilayer mist M can be separatelygenerated. Therefore, with mist-generating device 100 c, multilayer mistM does not need to be charged, unlike the case where multilayer mist Mis generated by electrostatic atomization. Therefore, voltage applyingunit 40 shown in FIG. 1 or other similar components can be omitted.Therefore, mist-generating device 100 c can be expected to be furtherreduced in size.

A portion of discharging surface 620 around discharging port 600preferably projects in the direction in which discharge liquid 610 isdischarged.

FIG. 21 is a top view showing a configuration of mist-generating device100 d according to Variation 1 of this embodiment. In FIG. 21,illustration of some components of mist-generating device 100 d, such ascontrol unit 73, supplying units 211 to 213, is omitted.

As shown in FIG. 21, mist-generating device 100 d differs frommist-generating device 100 c in configuration of microchannel chip 303of droplet generating unit 300 d.

Discharging surface 621, which is a side surface of microchannel chip303 in which discharging port 600 is formed, projects in the directionin which discharge liquid 610 is discharged at a portion arounddischarging port 600. Specifically, inclined portion 630, which has asurface inclined toward the direction in which discharge liquid 610 isdischarged, is formed on discharging surface 621. As a result, dischargeliquid 610 is unlikely to adhere to discharging surface 621, comparedwith the case where inclined portion 630 is not formed.

Note that, although FIG. 21 shows inclined portion 630, which is aportion around discharging port 600 that projects in the direction inwhich discharge liquid 610 is discharged in top view, the part whereinclined portion 630 is formed is not limited thereto.

For example, inclined portion 630 may be formed in such a manner thatthe inclined surface around discharging port 600 projects in thedirection in which discharge liquid 610 is discharged in side view ofmicrochannel chip 303 (that is, when viewed from the direction that isparallel with the principal surface (upper surface) of microchannel chip303 and is parallel with discharging surface 621).

Although mist-generating unit 402 has been described as an air blower asan example, mist-generating unit 402 has only to be able to atomizedischarge liquid 610 and is not limited to the air blower. For example,mist-generating unit 402 may be a vibration generating device thatatomizes discharge liquid 601 by causing vibrations of microchannel chip302 or 303.

Other Embodiments

Although mist-generating devices according to the present invention havebeen described with regard to various embodiments and variationsthereof, the present invention is not limited to the embodiments andvariations described above.

For example, in the embodiments described above, multilayer mist M ischarged by electrostatic atomization or by charging electrode 30 a shownin FIG. 8. However, in order to charge multilayer mist M, third liquidL3 yet to be atomized may be charged in advance. That is, multilayermist M may be generated by charging third liquid L3 containingfunctional droplet L generated by droplet generating unit 300 andatomizing charged third liquid L3 containing functional droplet L.

According to such a method, atomization and charging of third liquid L3containing functional droplet L can be separately performed, so that theamount of multilayer mist M generated and the amount of charge ofmultilayer mist M can be separately controlled. Therefore, according tosuch a method, the amount of multilayer mist M generated can becontrolled to a desired amount.

The process of charging third liquid L3 is not particularly limited. Forexample, an electrode electrically connected to the voltage applyingunit may be arranged in container 10, and a voltage may be applied tothe electrode to charge third liquid L3 in container 10. Note that thepredetermined voltage applied by the voltage applying unit may be apulse voltage, a pulsating voltage, or an alternating-current voltage.

Multilayer mist M does not always need to be charged with electriccharge E. According to the concept of the present invention, themist-generating device may not charge multilayer mist M with electriccharge E.

For example, in the embodiments described above, an example has beenshown in which electrode support plate 21 is arranged to cover the topsurface of third liquid L3, and nozzle 26 projects in an upwarddirection. However, the present invention is not limited thereto. Forexample, electrode support plate 21 may cover the bottom surface or sidesurface of third liquid L3, and a plurality of nozzles 26 may project ina downward direction, a sideward direction, or a slanting direction. Thedirection in which the mist-generating device according to the presentinvention sprays multilayer mist M is not limited to the upwarddirection but can be the downward direction, the sideward direction, orthe slanting direction.

For example, electrode support plate 21 and nozzle 26 of ejection plate20 may be integrally formed. Ejection plate 20 may be integrally formedby injection molding of a metal material or a resin material, forexample.

For example, first electrode 30 may not be a flat plate-shaped electrodeand may be an electrode plate smoothly curved, for example. Through-hole32 may pass through the electrode plate in the thickness direction orpass through the electrode plate in the direction in which nozzle 26projects.

For example, in the embodiments described above, droplet generatingunits 300, 300 a, and 300 b generate functional droplet L in thirdliquid L3. The mist-generating device may generate functional droplet Lin third liquid L3 by the droplet generating unit first generatingfunctional droplet L and the supplying unit then supplying functionaldroplet L into third liquid L3.

For example, in the embodiments described above, supplying unit 210 is apump, and functional droplet L generated by droplet generating unit 300is supplied to third liquid L3 in container 10 by supplying unit 210.For example, when droplet generating unit 300 is arranged on top ofcontainer 10, and the amount of first liquid L1 and second liquid L2introduced to microchannel chip 301 is controlled by control unit 70,that is, when control unit 70 controls the generation of functionaldroplet L, the supplying unit may be piping that introduces functionaldroplet L generated by droplet generating unit 300 into third liquid L3in container 10.

For example, in the embodiments described above, an example has beenshown in which electrode support plate 21 is arranged to cover the topsurface of first liquid L1 and second liquid L2, and nozzle B26 projectsin an upward direction. However, the present invention is not limitedthereto. For example, electrode support plate 21 may cover the bottomsurface or side surface of first liquid L1 and second liquid L2, andnozzle B26 may projects in a downward direction, a sideward direction,or a slanting direction. The direction in which mist-generating deviceB100 according to the present invention sprays multilayer mist BM is notlimited to the upward direction but can be the downward direction, thesideward direction, or the slanting direction.

For example, electrode support plate B21 and nozzle B26 of ejectionplate B20 may be integrally formed. Ejection plate B20 may be integrallyformed by injection molding of a metal material or a resin material, forexample.

For example, first electrode B30 may not be a flat plate-shapedelectrode and may be an electrode plate smoothly curved, for example.Through-hole B32 may pass through the electrode plate in the thicknessdirection or pass through the electrode plate in the direction in whichnozzle B26 projects.

For example, in the embodiments described above, nozzle B26 includesfirst nozzle part B27, and second nozzle part B28 that covers the outerperiphery of first nozzle part B27 at a distance. Nozzle B26 may includea third nozzle part that covers the outer periphery of second nozzlepart B28 at a distance. With such a configuration, first liquid L1 canbe covered by multiple layers of liquid.

For example, the mist-generating device may further include aconventional so-called single-layer nozzle having one discharging port,in addition to nozzle B26 in which first discharging port B29 a andsecond discharging port B29 b are formed.

For example, first liquid L1 may be an aqueous liquid containinghypochlorous acid having a disinfection or other effect, or an oilyliquid containing a perfume, for example. For example, second liquid L2may also be an aqueous liquid containing hypochlorous acid having adisinfection or other effect, or an oily liquid containing a perfume,for example.

The thickness of second liquid L2 in multilayer mist BM may beappropriately modified according to conditions, such as the rate ofvolatilization of second liquid L2, the weight of multilayer mist BM, orthe temperature, humidity, composition of the air. The thickness ofsecond liquid L2 can be set so that second liquid L2 volatilizes or islost to expose first liquid L1 to the air until multilayer mist BMreaches to a predetermined distance, which is arbitrarily determined inadvance.

For example, the mist-generating device may be provided with an airblower having a fan or the like, in order to make the generatedmultilayer mist travel far or fix the direction of travel of thegenerated multilayer mist.

Furthermore, in the foregoing embodiments, all of the elements such ascontroller 70 may be configured using dedicated hardware, or may beimplemented by executing software programs suitable for the respectiveelements. Each of the elements may be implemented by a program executingcomponent, such as a central processing unit (CPU) or processor, readingand executing a software program recorded on a recording medium such asa hard disk drive (HDD) or a semiconductor memory.

Furthermore, elements such as controller 70 may be configured using oneor more electronic circuits. The one or more electronic circuits mayeach be a general-purpose circuit or a dedicated circuit.

The one or more electronic circuits may include, for example, asemiconductor device, an integrated circuit (IC), or a large-scaleintegration (LSI). The IC or LSI may be integrated in a single chip orseveral chips. Although referred to here as IC or LSI, the name maychange depending on the scale of integration, and may be referred to asa system LSI, very large scale integration (VLSI), or ultra large scaleintegration (ULSI). Furthermore, a field programmable gate array (FPGA)that can be programmed after being manufactured may be used for the samepurpose.

Furthermore, general or specific aspects of the present invention may beimplemented as a system, an apparatus, a method, an integrated circuit,a computer program, or a non-transitory computer-readable recordingmedium such as an optical disc, an HDD, or a semiconductor memory onwhich the computer program is recorded, or may be implemented as anycombination of a system, an apparatus, a method, an integrated circuit,a computer program, and a recording medium.

Aside from the foregoing, forms obtained by various modifications to therespective embodiments that may be conceived by a person of skill in theart as well as forms realized by arbitrarily combining structuralcomponents and functions in the respective embodiments without departingfrom the spirit of the present invention are also included in thepresent invention.

REFERENCE MARKS IN THE DRAWINGS

26, B26, B26 a, B26 b nozzle

30, B30, B30 a first electrode

30 a charging electrode

100, 100 a, 100 b, 100 c, 100 d, B100 mist-generating device

210, 211, 212, 213, B300 supplying unit

300, 300 a, 300 b, 300 c, 300 d droplet generating unit

301, 301 a, 302, 303 microchannel chip

311, 311 a, 311 b first liquid channel

321, 321 a, 321 b second liquid channel

322, 322 a mixing channel

331, 331 a, 331 b, 331 c, 331 d third liquid channel

400, 401, 402 mist-generating unit

600 discharging port

610 discharge liquid

620, 621 discharging surface

630 inclined portion

L functional droplet

L1 first liquid

L2 second liquid

L3 third liquid

M, M1, M2, BM, BM1 multilayer mist

1. A mist-generating device, comprising: a droplet generating unitconfigured to generate, in a third liquid, a functional dropletincluding a first liquid that is spherical and a second liquid thatcovers an entirety of the first liquid and has a volatility lower than avolatility of the first liquid; and a mist-generating unit configured togenerate a multilayer mist obtained by atomizing the third liquidcontaining the functional droplet into a mist.
 2. The mist-generatingdevice according to claim 1, further comprising: a supplying unitconfigured to supply the third liquid containing the functional dropletgenerated by the droplet generating unit to the mist-generating unit. 3.The mist-generating device according to claim 1, wherein the secondliquid is one of a biomaterial and a biocompatible material.
 4. Themist-generating device according to claim 1, wherein one of the firstliquid and the second liquid is oily and the other of the first liquidand the second liquid is aqueous.
 5. The mist-generating deviceaccording to claim 1, wherein the third liquid has a volatility higherthan the volatility of the second liquid.
 6. The mist-generating deviceaccording to claim 1, wherein the functional droplet has a particle sizeof at most 10 μm.
 7. The mist-generating device according to claim 1,wherein the droplet generating unit is a microchannel chip including: afirst liquid channel through which the first liquid passes; a secondliquid channel through which the second liquid passes; a mixing channelconnected to the first liquid channel and the second liquid channel, forcovering the entirety of the first liquid with the second liquid; and athird liquid channel connected to the mixing channel, for covering anentirety of the first liquid and the second liquid with the thirdliquid.
 8. The mist-generating device according to claim 1, wherein themist-generating unit is an ultrasonic vibration generator configured togenerate the multilayer mist by atomizing the third liquid containingthe functional droplet by applying an ultrasonic vibration to the thirdliquid containing the functional droplet.
 9. The mist-generating deviceaccording to claim 1, further comprising: a charging electrode forcharging the multilayer mist.
 10. The mist-generating device accordingto claim 1, wherein the mist-generating unit includes: a nozzleconfigured to discharge the third liquid containing the functionaldroplet; and a first electrode disposed opposite to the nozzle andconfigured to generate the multilayer mist by atomizing the third liquidcontaining the functional droplet by applying a voltage to the thirdliquid containing the functional droplet discharged from the nozzle.